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***•••*•**•••••• 




Disclosure to Promote the Right To Information 

Whereas the Parliament of India has set out to provide a practical regime of right to 
information for citizens to secure access to information under the control of public authorities, 
in order to promote transparency and accountability in the working of every public authority, 
and whereas the attached publication of the Bureau of Indian Standards is of particular interest 
to the public, particularly disadvantaged communities and those engaged in the pursuit of 
education and knowledge, the attached public safety standard is made available to promote the 
timely dissemination of this information in an accurate manner to the public. 



Mazdoor Kisan Shakti Sangathan 
'The Right to Information, The Right to Live' 



IS/IEC 1131-2 (1992): Programmable Controllers, Part 2: 
Equipment Requirements and Tests [ETD 18: Industrial 
Process Measurement and Control] 




Jawaharlal Nehru 
'Step Out From the Old to the New' 



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Satyanarayan Gangaram Pitroda 
Invent a New India Using Knowledg 



Bhartrhari — Nitisatakam 
"Knowledge is such a treasure which cannot be stolen" 





BLANK PAGE 




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PROTECTED BY COPYRIGHT 



is/iic tm-t atii) 

^_ ( Reaffirmed 2003 ) 

indiBH Standard 
PROGRAMMABLE CONTROLLERS 

PART 2 I^UU^MENT REQUmEliilfT* AND TESTS 



ICS 29.Ma40 



9 Bid i9» 

BUREAU OF INDIAN STANDARDS 

lymiUK fiHAVAN, 8 BAHADUR SHAH ZAFA^ MAfla 

NEW DiLHI 110002 



IS/IEC 1131-2 (1992) 

CONTENTS 

General 7 

1 .1 Scope 7 

1 .2 Object of the standard 7 

1 .3 Object of tfiis part 8 

1 .4 Definitions 8 

1 .5 Normative references 15 

Service conditions and physical environment related requirements 17 

2.1 Normal service conditions 17 

2.1.1 Physical environmental conditions 17 

2.1 .2 Electrical service conditions and requirements 18 

2.1 .3 Mechanical service conditions and requirements 19 

2.2 Special service conditions 21 

2.3 Requirements for transport and storage of modules and subassemblies 21 

2.3.1 Temperature 21 

2.3.2 Relative humidity 21 

2.3.3 Atmospheric pressure 21 

2.3.4 Free falls 21 

2.3.5 Other conditions 22 

2.3.6 Information to be provided by the manufacturer 22 

2.4 Transport and storage conditions of PC-systems incorporated in complete 

control assemblies 22 

Electrical requirements 22 

3.1 General 22 

3.2 A.C. and d.c. power supply 24 

3.2. 1 Incoming power supply 24 

3.2.2 Memory back-up 25 

3.2.3 Information to be provided by the manufacturer , 26 

3.3 Digital l/Os 27 

3.3.1 Digital inputs (current sinking) 28 

3.3.2 Current sourcing digital outputs for alternating currents 32 

3.3.3 Current sourcing digital outputs for direct current 35 

3.4 Analog l/Os 37 

3.4.1 Analog inputs 37 

3.4.2 Analog outputs 39 

3.5 Communication interfaces 41 

3.5.1 General requirements 41 

3.5.2 Information to be provided by the manufacturer 41 

3.6 Main processing unit(s) and memory{ies) of the PC-system 41 

3.6.1 General 41 

3.6.2 Requirements 41 

3.6.3 Information to be provided by the manufacturer 41 

3.7 Remote input/output stations (RIOSs) 42 

3.7.1 Requirements 42 

3.7.2 Information to be provided by the manufacturer 42 

1 



IS/IEC 1131-2 (1992) 

3.8 Peripherals (PADTs, TEs, MMIs) 43 

3.8.1 Requirements 43 

3.8.2 Information to be provided by the manufacturer 44 

3.9 Noise immunity and emitted noise 44 

3.9.1 Electrical noise immunity requirements 44 

3.9.2 InforrViation to be provided by the manufacturer 45 

3.9.3 Emitted noise 45 

3.10 Dielectric properties 46 

3.10.1 General 46 

3.10.2 Dielectric withstand requirements 46 

3.10.3 Information to be provided by the manufacturer 47 

3.1 1 Self-tests and diagnostics 48 

3.1 1 .1 General 48 

3.1 1 .2 Requirements 48 

3.1 1 .3 Information to be provided by the manufacturer 48 

4 Mechanical requirements 48 

4.1 General 48 

4.2 Protection against electrical shock hazard 49 

4.2.1 Class I equipment 49 

4.2.2 Class II equipment 49 

4.2.3 Class III equipment and safety extra low voltage (SELV) circuits 50 

4.3 Clearance and creepage distances requirements 50 

4.3.1 Clearances relating to normal overvoitage category 51 

4.3.2 Clearances for micro-environment where the voltages are known and 
controlled 52 

4.3.3 Creepage distances for basic and supplementary insulation 53 

4.3.4 Creepage distances for reinforced insulation 58 

4.4 Flammability requirements for insulating materials 58 

4.4.1 Non-metallic materials 58 

4.4.2 Temperature limits of materials 58 

4.5 Enclosures 59- 

4.5.1 Evaluation of enclosures for open equipment (power dissipation) 59 

4.5.2 Moving parts in non-portable devices 60 

4.5.3 Enclosures for portable equipment .60 

4.6 Terminal connection mechanical requirements 61 

4.6.1 Constructional requirements 61 

4.6.2 Connecting capacity 61 

4.6.3 Information to be provided by the manufacturer 62 

4.7 Provisions for protective earthing 62 

4.7.1 Constructional requirements 62 

4.7.2 Protective earthing terminal 63 

4.8 Functional earthing 63 

4.9 Interconnecting cables and cords 63 

4.9.1 General 63 

4.9.2 Wiring internal to the PC-system (internal wiring) 63 

4.9.3 Connectors and wiring externals to the PC-system (external wiring) 64 

2 



IS/lEC 1131-2 (1992) 

4,9.4 Internal and external wiring 64 

4.10 Plugging/unplugging of removable units 64 

4.1 1 Battery requirennents 65 

4.1 1 .1 General 65 

4.1 1 .2 Non-rechargeabie batteries 65 

4.1 1 .3 Memory back-up 65 

4.12 Markings and identification 65 

4.12.1 General marking requirements 65 

4.12.2 General identification requirements 66 

5. Information to be provided by the manufacturer 67 

5.1 General 67 

5.2 Index of information to be provided 67 

5.3 Type and contents of written documentation 69 

5.3.1 Catalogues and datasheets 69 

5.3.2 User's manuals 69 

5.3.3 Technical documentation 69 

5.4 Information on compliance with this standard 69 

5.5 Information on reliability 69 

5.6 Information on safety 70 

6. Tests and verifications 70 

6.1 General 70 

6.2 Compliance with this standard 70 

6.3 Type tests .■ 71 

6.3.1 Equipment to be tested 71 

6.3.2 Verification procedure 72 

6.3.3 General conditions for tests 73 

6.3.4 Climatic tests 74 

6.3.5 Mechanical tests 77 

6.3.6 Electrical tests ^ 84 

6.3.7 Verification of a.c. and d.c. power supply characteristics 91 

6.3.8 Verification of input/output characteristics 98 

6.3.9 Verification of MPU characteristics 102 

6.3.10 Verification of remote I/O stations 102 

6.3.1 1 Verification of peripheral characteristics 103 

6.3.12 Verification of basic PC-system self-tests and diagnostics 103 

6.3.13 Verification of markings and manufacturer's documentation 103 

6.4 Routine tests 104 

6.4.1 Dielectric strength tests 104 

6.4.2 Protective earthing continuity test (withstand test) 106 

ANNEXES 

A Illustration of PC-system hardware definitions 107 

B Input table equations 1 08 

C Recommended higher immunity levels for electrical noise tests 109 

D Correction factors for test voltages 110 

E Testing of protected outputs 111 



As in the Original Standard, this Page is Intentionally Left Blank 



IS/IEC 1131-2 (1992) 



Indian Standard 



PROGRAMMABLE CONTROLLERS 

PART 2 EQUIPMENT REQUIREMENTS AND TESTS 

NATIONAL FOREWORD 

This Indian Standard which is identical to lEC Publication 1131-2 (1992), issued by the International 
Electrotechntcal Commission (lEC), was adopted by the Bureau of Indian Standards on the recommen- 
dation of the Industrial Process Measurement and Control Sectional Committee (ET 18) and approval of 
the Electrotechnical Division Council. 

This standard constitutes Part 2 of a series of standards on Programmable Controllers and their associated 
peripherals and should be read in conjunction with the other parts of the series. 

The following standards are being brought out in this series: 

Programmable controllers: 
Part 1 General information 
Part 2 Equipment requirements and tests 
Part 3 Programming languages 
Part 4 User guidelines 
Part 5 Communications 



The text of lEC Standard has been approved as suitable for publication as Indian Standard without 
deviations. 

CROSS REFERENCES 

In this adopted standard, reference appears to certain International Standards for which Indian Standards 
also exist. The corresponding Indian Standards which are to be substituted in their place are listed below 
along with their degree of equivalence for the editions indicated: 
International Standard 



IEC38(1983) 
lEC 50-151 (1978) 
lEC 50-441 (1984) 
IEC60-1 (1989) 



lEC 68-2-1 (1990) '^ 
lEC 68-2-2 (1974) 
lEC 68-2-3 (1969) 
lEC 68-2-6 (1982) 
IEC-68-2-14(1984) 
lEC 68-2-27 (1987) 
lEC 68-2-30 (1980) 
lEC 68-2-31 (1969) 
lEC 68-2-32 (1975) 

IEC85(1984) 



> 



^ 



lEC 112 (1979) 



Corresponding Indian Standard Degree of 

Equivalence 

IS 1 2360 : 1 988 Voltage bands for electrical installa- Technicaly 

tions including preferred voltages and frequency equivalent 

IS 1 885 (Part 57) : 1 982 Electrotechnical vocabulary: Technically 

Part 57 Electric and magnetic circuits equivalent 

IS 1 885 (Part 1 7) : 1 979 Electrotechnical vocabulary; Technically 

Part 1 7 Switchgear and controlgear {first revision) equivalent 

IS 2071 (Part 1 ) : 1 993 High voltage test techniques: Identical 
Part I General definitions and test requirements 
{second revision) 



IS 9000 Basic environmental testing for electronic 

and electrical items (series) Technically 

IS 9001 Guidance for environmental testing (series) equivalent 

IS 9002 Equipment for environmental tests for 

electronic and electrical items (series) 



IS 1 271 : 1 985 Thermal evaluation and classification Technically 

of insulation {first revision) equivalent 

IS 2824 : 1 975 Method of determining the compara- Technicaly 

five tracking index of solid insulating materials under equivalent 
moist conditions {first revision) 



IS/IEC 1131-2(1992) 



International Standard 
lEC 529 (1989) 
lEC 664 (1980) 
lEC 695-2-1 (1980) 
lEC 707 (1981) 



lEC 947-1 (1988) 
lEC 947-5-1 (1990) 

!EC 950 (1991) 



Corresponding Indian Standard Degree of 

Equivalence 

IS 4691 . 1985 Degrees- of protection provided by Technically 

enclosure for rotating electrical machinery equivalent 

SP 39 : 1 987 Guide for insulation co-ordination within Technically 

low voltage systems equivalent 

IS 1 1000 (Part 2/SeG 1) . 1984 Fire hazard testing: Part identical 

2 Test methods. Section 1 Glow wire test and guidance 

IS 1 1 731 (Part 1 ) : 1 986 Method of test for the deter- Technically 

mination of the flammabillty of solid electrical insulating equivalent 

materials : Part 1 Horizontal specimen method 

IS 11731 (Part 2) : 1986 Method of test for the 

determination of the flammability of solid electrical 

insulating materials : Part 2 Vertical specimen method 

IS 1 3947 (Part 1 ) : 1 993 Low-voltage switchgear and Identical 

controlgear ; Part 1 General rules 

IS 13947 (Part 5/Sec 1) : 1993 Low-voltage Identical 

switchgear and controlgear; Part 5 Control circuit 
devices and switching elements, Section 1 Electro- 
mechanical control circuit devices 



IS 10422 : 1982 Requirement and test methods for Technically 

safety of data processing equipment equivalent 

The concerned technical committee has reviewed the provisions of following lEC/ISO standards referred 
to in this adopted standard and has decided that it is acceptable for use in conjunction with this standard. 

lEC 255-4 (1976) Electrical relays — Part 4 : Single input energizing quantity measuring relays with 
dependent specified time 

lEC 364-4-443 (1990) Electrical installations of buildings — Part 4 : Protection for safety — Chapter 44 : 
Protection against overvoltages — Section 443 ; Protection against overvoltages of atmospheric origin or 
due to switching 

lEC 41 7 (1 973) Graphical symbols for use on equipment-index, survey and compilation of the single sheets 
lEC 445 (1988) Identification of equipment terminals of certain designated conductors, including general 
rules of an alphanumeric system 

tEC 801-2 (1991) Electromagnetic compatibility for industrial-process measurement and control equip- 
ment — Part 2 : Electrostatic discharge requirements 

lEC 801-3 (1984) Electromagnetic compatibility for industrial-process measurement and controJ equip- 
ment — Part 3 : Radiated electromagnetic field requirements 

lEC 801-4 (1988) Electromagnetic compatibility for industrial-process measurement and control equip- 
ment — Part 4 -. Electrical fast transient/burst requirements 

lEC 801-5 (...) Electromagnetic compatibility for industrial-process measurement and control equip- 
ment — Part 5 : Surge immunity requirements {under consideration) 

lEC 947-5-2 (1992) Low voltage switchgear and controlgear — Part 5 : Control circuit devices and 
switching elements — Section 2 : Proximity switches 

ISO/I EC 9506-1 (1 990) Industrial automation systems — Manufacturing message specification — Part 1 : 
Service definitions 

ISO/IEC 9506-2 (1 990) Industrial automation systems — Manufacturing message specification — Part 2 : 
Protocol specification 

Only the English language text given in the International Standard has been retained while adopting it as 
Indian Standard, and as such the page numbers given here are not the same as in lEC publication. 

For the purpose of deciding whether a particular requirement of this standard is complied with, the final 
value, observed or calculated, expressing the result of a test, shall be rounded off in accordance with IS 2 . 
1 960 'Rules for rounding off numerical values {revised)'. The number of significant places retained in the 
rounded off value should be the same as that of the specified value in this standard. 



rS/lEC 1131-2(1992) 



1 General 

1 . 1 Scope 

This International Standard applies to programmable controllers and their associated 
peripherals such as programming and debugging tools (PADTs), test equipment (TE) and 
man-machine interfaces (MMIs), etc. 

Equipment covered in this standard is intended for use in overvoltage category 11 (see 
lEC 364-4-443), in low voltage installations, where the rated mains supply voltage does 
not exceed 1 000 V a.c. (50/60 Hz), or 1 500 V d.c, for the control and command of 
machines and industrial processes. 



Programmable controllers and the associated peripherals are considered as components 
of a control system and may be provided as enclosed or open equipment. Therefore, this 
standard does not deal with the automated system In which the programmable controller 
system is but one basic component among many others including its application program. 



Since programmable controllers are component devices, overall automated system safety 
including installation and application is beyond the scope of this standard. For further 
information, refer to lEC 1131-4 which is intended to help users in reducing the risks. How- 
ever, electrical noise immunity and error detecting of the PC-system operation such as the 
use of parity checking, self-testing diagnostics, etc., are addressed. 



1 .2 Object of the standard 

The purposes of this standard are: 

- to establish the definitions and identify the principal characteristics relevant to the 
selection and application of programntable controllers and their associated peripherals; 

- to specify the minimum requirements for the functional characteristics, service 
conditions, construction characteristics, general safety, and tests applicable to program- 
mable controllers and the associated peripherals; 

- to define, for each of the most commonly used programming languages: major field 
of application, syntactic and semantic rules, simple but complete basic sets of program- 
ming elements, applicable tests and means by which manufacturers may expand or 
adapt those basic sets to their own programmable controller implementations; 

' to give general tutorial information and application guidelines to the user; 



IS/IEC 1131-2(1992) 

— lO u8iin8 tiio cciTiiTiunicsticn uctween proQi'smmsbic ccntroliers snd.othsr elsctronic 
systems using the Manufacturing Message Specification (MMS) defined in 
ISO/IEC 9506. 



1 .3 Object of this part 
This part specifies 

- the electrical, mechanical and functional* requirements for programmable control- 
lers and the associated peripherals and the service, storage and transportation 
conditions that apply; 

- the information that the manufacturer is required to supply; 

- the test methods** and procedures that are to be used lor the veritication of 
compliance of programmable controllers and their associated peripherals with the 
requirements. 

1 .4 Definitions 

NOTE - This clause contains the definitions of terms which are more specific to the object of this part in 
order to make it more self-contained. Terms of general use are defined in part 1. 

1.4.1 accessible part: 

1) A part which can be touched by the standard jointed test finger (see I EC 529) . 

2) A conductive part which can readily be touched and which is not normally live, but 
which may become live under fault conditions. [IEV441-11-10 modified] 

1.4.2 basic PC-system(s): Representative contiguration(s) used for type tests. See 
figure 1, in 3.1 and 6.3.1. 

1.4.3 battery: An electrochemical energy source which may be rechargeable or non- 
rechargeabte. 

1.4.4 circuit, class I, class II, class III: see equipment (1.4.16). 

1.4.5 clearance: The shortest distance between two conductive parts, or between a 
conductive part and the bounding surface of the equipment, measured through air. The 
bounding surface is the outer surface of the enclosure considered as though metal foil is 
pressed into contact with accessible surfaces of insulating material. 

1.4.6 coating, protective: A coating of suitable insulating material that covers the clear- 
ance and/or creepage distance of the printed board and conforms to the surface of the 
board in such a manner that the environment is excluded and the clearance and/or 
creepage distance can withstand the required impulse and continuous potentiat. 



** The tests are type tests or production routine tests, and not tests related to the ways programmable 
controller systems are applied. 

8 



IS/IEC 1131-2(1992) 

NOTE - Coating is normally applied to exclude the effects of atmosphere and to increase the dielectric 
properties of the clearance and/or creepage distances which would not normally be adequate without 
coating. Less effective coating may exclude the atnosphere but cannot be relied on to enhance the 
dielectric properties, 

1 .4.7 comparative tracking Index (CTI): The numerical value of the maximum voltage at 
which a material withstands 50 drops of NH^CI solution (ammonia chloride) without 
tracking (see lEC 112). 



1.4.8 coverage factor (for modules, units, external wiring, internal wiring, removable 
cables, interconnections and functions): The percentage of modules, units, external 
wirings, internal wirings, removable cables, interconnections, functions, whose removal, 
absence or failure is detected by built-in test functions or by a suitable test program along 
with a proper functioning verification procedure. See 6.3.2. 



1.4.9 creepage distance: The shortest path between two conductive parts, or between a 
conductive part and bounding conducting surface of the equipment, measured along the 
surface of the insulation. 

1 .4.10 current sinking: The act of receiving current. 

1.4.1 1 current sourcing: The act of supplying current. 

1.4.12 diversity factor (of an output module): Ratio of the permissible total x:urrent 
(total output current) to the sum of all maximum rated currents of multi-channel output 
module operating at the most adverse combination of normal service conditions. 



1.4.13 earth: The conducting mass of the Earth, whose electric potential at any point is 
conventionally taken as zero. (lEV 151-01-07] (Synonymous with protective earth.) 

1.4.14 earth, functional, protective^ 

1) functional earth: A low impedance path between electrical circuits and earth fdr 
non-safety purposes such as noise immunity improvement. 

2) protective earth: A low impedance path under fault conditions including high 
voltage and/or current between the electrical circuit and earth to minimize the risk to 
the operator. 

1.4.15 enclosure: A final mounting housing which provides protection against acci- 
dental contact with live and/or moving parts. (See equipment, open and equipment, 
enclosed.) 

1.4.16 equipment (t>r circuit) class I, class It, class Ul: Class numbers designate the 
means by which electric shock protection is maintained in normal use and likely fault 
conditions of the installed equipment. 

1) class I circuit or equipment: Circuit or equipment in which protection against 
electric shock does not rely on basic rnsulation only, but which includes an additional 
safety precaution in that accessible conductive parts are connected to the protective 



IS/IEC 1131-2(1992) 

earthing conductor in the fixed wiring of the installation in such a way that they cannot 
become live in the event of a failure of the basic insulation. For equipment intended for 
use with a flexible cord, this provision includes the protective earthing conductor as 
part of the flexible cord. 

NOTE - Class I equipment may have parts with double instlation or reinforced insulation, or parts operat- 
ing at safety extra-low voltage. 

2. Class II circuit or equipment: Circuit or equipment in which protection against 
electric shock does not rely on basic insulation, but In which additional safety pre- 
cautions, such as double insulation or reinforced insulation are provided, there being 
no provision for protective earthing or reliance upon installation conditions. 

Such equipment may be of one of the following types: 

I) insulation-encased class II equipment: equipment having a durable and 
substantially continuous enclosure of insulating material which envelops all con- 
ductive parts, with the exception of small parts, such as nameplates, screws and 
rivets, which are isolated from parts at hazardous voltage by insulation at least 
equivalent to reinforced insulation; 

ii) metal-encased class II equipment: equipment having a substantially continuous 
metal enclosure, in which double insulation is used throughout, except for those 
parts wher& reinforced insulation is used; 

iii) equipment which is a combination of types i) and ii). 

NOTES 

1 The insulated enclosure of a class II equipment may form a part of the whole of the supplementary 
insulation or of the reinforced insulation. 

2 If equipment with doutile insulation and/or reinforced insulation throughout has a protective earthing 
terminal or contact, it is deemed to be of class I construction. 

3 class II equipment may have parts operating at safety extra-low voltage. 

3) Class III circuit or equipment: Circuit or equipment in which protection against 
electric shocic is pro^/ided by circuits supplied by safety extra-low voltage (SELV) and 
where voltages generated do not exceed the limits for SELV. 



1.4.17 equipment, enclosed: Equipment which is enclosed on all sides with the pos- 
sible exception of its mounting surface to prevent personnel from accidentally touching live 
or moving parts contained therein and to protect tlie equipment against ingress of medium 
size solid foreign bodies, and meeting requirements of mechanical strength, flammability, 
and stability (where applicable). 

1.4.18 equipment, fixed: Equipment which is part of the permanent installation. 

1.4.19 equipment, hand-held portable: Equipment which is intended to be held in one 
hand while being operated with the other hand. 

1.4.20 equipment, open: Equipment which may have live electrical parts accessible, 
e.g. a main processing unit. An open equipment is to be incorporated into other 
assemblies manufactured to provide safety. 



10 



IS/IEC 1131-2(1992) 

1.4.21 equipment, on-line pluggable: Equipment which can be plugged or unplugged 
from the PC-system at any time including when the PC-system is operating, without 
disturbing or disrupting the normal operation of the PC-system and without any increased 
risk to the operator and the application. 

1 .4.22 equipment, portable: Enclosed equipment which is intended to be transported by 
hdnd-carrying, such as programming and debugging tools (PADTs) and test equipment (TE). 



1.4.23 hazardous voltage: Voltage exceeding 42,4 V peak or d.c, existing in a circuit 
which does not meet the requirement for a limited energy circuit. 

1 .4.24 Immunity: Ability of the PC-system to be unaffected or to maintain Its operation 
within limits specified by the manufacturer when submitted to influencing quantities 
specified in this standard. 

1 .4.25 Input, digital, type 1/type 2 (type 1 digital input, type 2 digital input): 

1) type 1 digital input: Digital input for sensing signals from mechanical contact 
switching devices, such as relay contacts, pushbuttons, switches, etc.; type 1 digital 
inputs may not be suitable for use with solid state devices such as sensors, proximity 
switches, etc. 

2) type 2 digital input: Digital input for sensing signals from solid state switching 
devices ^uch as 2-wire proximity switches. This class could also be used for type 1 
applications. 

1 .4.26 Insulation (basic, supplementary, double, reinforced): 

1) basic Insulation: insulation applied to live parts to provide basic protection against 
electric shock. 

2) supplementary Insulation: Independent insulation applied in addition to basic 
insulation in order to ensure protection against electric shock in the event of a failure of 
the -basic insulation. 

3) double Insulation: Insulation comprising both basic insulation and supplementary 
insulation. 

4) reinforced insulation: Single insulation system applied to live parts which provides 
a degree of protection against electric shock equivalent to double insulation under the 
conditions specified in this standard. 

NOTE - The term 'insulation system* does not imply that the insulation must be in one homogeneous 
piece. It may comprise several layers which cannot be individually tested as supplementary or basic 
insulation. 

1.4.27 interface: Stiared boundary between a considered system and another system, 
or between parts of a system, through which information is conveyed. See 3.1. 

1.4.28 Isolated (devices, circuits): Devices, circuits with no galvanic connection 
between them. 

1.4.29 live part: Any conductor or conductive part which is at a voltage in normal use. 



IS/IEC 1131-2(1992) 

1 .4.30 mains power supply: Power from the conductors/mains of the permanent instal- 
lation of the building at the supply voltage to the PC-system. 



1.4.31 main processing unit (IVIPU): The portion of the PC-system which interprets or 
executes the (main parr of the) application program. The MPU may Include power supply, 
memory, and l/Os. See annex B of lEC 1131-1 and 3.1, 3.6 and annex A of this part. 



1.4.32 man-machine interface (MIMI): Manufacturer's catalogued peripheral equipped 
with pushbuttons, lamps, keyboards, displays or equivalent, intended as operator inter- 
face, such as motor control/monitor panel, general purpose operator interface, etc. 



MMIs may be part of the permanent installation (e.g. mounted on front panels, doors, 
boards, etc.) or not. 

1.4.33 material group: Classification of insulating materials in terms of comparative 
tracl^ing index (CTi) range (see 4.3.3). 

1.4.34 micro-environment: Ambient conditions which surround the clearance or 
creepage distance under consideration. 

NOTE - The micro-environment of the clearance or creepage distance and not the environment of the 
equipment determines the effect of the insulation. The micro-environment may be better or worse than the 
environment of the equipment. It includes all factors influencing the insulation, such as climatic,, electro- 
magnetic, pollution, etc. (See lEC 664 for further information.) 



1.4.35 module: Device such as an t/0 board assembly which plugs into a back plane 
or base. 

1.4.36 multi-circuit module: Module containing multiple isolated circuits. With respect 
to I/O modules, a module containing multiple isolated user signal interfaces. 

1.4.37 multi-channel module: Module containing multiple input and/or output user 
signal interfaces. A multi-channel module may or may not be a multi-circuit module. 

1.4.38 output, not-protected, protected, sliort-circuit proof: 

See 3.3.2.2 and 3.3.3.2. 

1.4.39 overvoltage category (of a circuit or within an electrical system): A conven- 
tional number based on limiting (or controlling) the values of prospective transient 
overvoltages occurring in a circuit (or within an electrical system having different nominal 
voltages) and depending upon the means employed to influence the overvoltages. 

NOTE - In an electrical system, the transition from one overvoltage category t0 another of lower category 
is obtained through appropriate means complying with interface requirements, such as an overvoltage 
protective device or a series-shunt impedance arrangement capable of dissipating, absorbing, or diverting 
the energy in the associated surge current, to lower the transient overvoltage value to that of the desired 
lower overvoltage category. 

1.4.40 PC-system: Synonymous with programmable controller system as defined in 
2.5.1 of lEC 1131-1. see annex A of lEC 1 1 31 -1 and annex A of this part. 

12 



IS/IEC 1131-2(1992) 
1 .4.41 permanent Installation: See annex A of lEC 1131-1 or annex A of tfiis part. 



1.4.42 pollution degree (in the micro-environment): For the purpose of evaluating 
clearances and creepage distances, the following three degrees of pollution in the micro- 
environment are established: 

1) pollution degree 1: No pollution or only dry, non-conductive pollution occurs. The 
pollution has no influence. 

2) pollution degree 2: Normally, only non-conductive pollution occurs. Occasionally, 
however, a temporary conductivity caused by condensation shall be expected. 

3) pollution degree 3: Conductive pollution occurs, or dry, non-conductive pollution 
occurs which becomes conductive due to condensation which is expected. 

NOTES 

1 The conductivity of a polluted insulatton is due to the deposition of foreign matter and moisture. 

2 The minimum clearances given for pollution degrees ? and 3 are based on experience rather than on 
fundamentaf data. 

1.4.43 protective earthing conductor, terminal, connection: See earth, protective 
(1.4.14). 

1.4.44 rated supply voltage: Mains voltage (for three-phase supply, the line-to-line 
voltage) for which the manufacturer has designed the apparatus. 



1.4.45 recurring pealc voltage: Peak value of a generated voltage whose characteristic 
is recurring at some specified period. Such recurring peak voltages are generally 
generated in switch-mode power supply circuits (a.c. or d.c. to d.c. converters). 
See 4.3.3.2. 

1.4.46 removable connector: Connecting means intended to be used for operation or 
maintenance servicing of the PC-system by the user. Pluggable modules, peripherals, etc. 
are generally connected to the rest of the PC-system by such means. 



1.4.47 safety extra-low voltage (SELV): A voltage which, under all operating 
conditions does not exceed 42,4 V peak or d.c. between conductors, or between any 
conductor and earth, in a circuit which is isolated from the mains power supply by means 
of a safety isolating transformer or an equivalent means. National regulations have to be 
considered for a correct isolation voltage rating. 



1.4.48 safety extra low-voltage circuit (SELV circuit): Circuit which is so designed 
and protected that under normal and single fault conditions the voltage between any two 
accessible parts, one of which may be earth or a conductive accessible part connected io 
earth, does not exceed the safety extra-low voltage and in which overvoltages higher than 
SELV are not generated. 

1.4.49 Subassembly: Synonymous with unit (1.4,53). 



13 



IS/IEC 1131-2(1992) 

1.4.50 temperature (ambient air): 

1) For enclosed non-ventilated equipment that is cooled by natural air convection, the 
equipment ambient air temperature is the room temperature 1 m away from the surface 
of the enclosure on a horizontal plane located at the vertical mid-point of the enclosure. 

2) For enclosed ventilated equipment, the equipment ambient temperature is the 
temperature of the incoming air. 

3) For open equipment, the ambient air temperature is the temperature of the incoming 
air immediately below the equipment. 

1.4.51 total output current (of an output module): The current that a multi-channel 
module operating at the most adverse combination of normal service conditions can 
supply without any part of it (insulation, terminals, exposed conductive parts, etc.) exceed- 
ing the specified temperature limits. 

NOTE - For a multi-channel module, the total output current is generally less than the sum of the output 
currents of the channels. 

1 .4.52 test (routine, type, immunity type, withstand type): 

1) routine test: Test to which each individual catalogued device is subjected during or 
after its manufacturing process to ascertain whether it complies with certain criteria. 

2) type test: Laboratory test to which one or several basic PC-systems or samples of 
catalogued devices is (are) subjected to ascertain that its (their) design(s) meet require- 
ments expressed in this standard. 

3) immunity type test (immunity test): Type test verifying that the basic PC-system 
operation is not altered by the application of specified influencing quantities which are 
intended to approximate normal service conditions. 

During the test, the basic PC-system executes appropriate test programs to be pro- 
vided by the manufacturer (see 6.3.2.2). 

NOTE - Some tests may allow temporary alteration of the basic PC-system operation within limits that 
must be then specified by the manufacturer. 

4) Withstand type test (withstand test); Type test verifying that the application of 
more severe influencing quantities to the basic PC-system does not impair its ability to 
assume its intended mission. Unless othenwise specified, the basic PC-system is not 
energized during the withstand test. After a specified recovery period, a proper function- 
ing verification procedure is performed as specified to checic visually and/or by 
measurement that the test had no detrimental effect on the basic PC-system. 



NOTE - The impact test (see 6.3.&.5.1) is classified as withstand test though it may affect the operability 
of the basic PC-system. 



1.4.&3 unit: For the purpose of this standard, a unit is an integral assembly (which may 
consist of modules plugged in or otherwise connected within the assembly) and which is 
connected to other units within the system by means of cables for permanently installed 
units and cables or other means for portable units. 



14 



IS/IEC 1131-2(1992) 

1.4.54 Wiring (interna), externai): 

1) Internal wiring: Wiring wiilch is inside the open or enclosed PC-system equipment. 

2) external wiring: Wiring of the PO-system equipment which is normally installed by 
the user. 

1.5 Normative references 

The lollowing normative documents contain provisions which, through reference in this 
text, constitute provisions of this part of lEC 1131. At the time of publication, the editions 
indicated were valid. All documents are subject to revision, and parties to agreements 
based on this part of lEC 1131 are encouraged to investigate the possibility of applying 
the most recent editions of the normative documents indicated below. Members of fEC and 
ISO maintain registers of currently valid International Standards. 

I EC 38: 1983, I EC standard voltages. 

lEC 50(151): 1978, International Electrotechnical Vocabulary- Chapter 151: Electrical and 
magnetic devices. 

I EC 50(441): 1984, International Electrotectinical Vocabulary - Chapter 441: Switchgear. 
controlgear and fuses. 

lEC 60-1: 1989, High-voltage test techniques - Part 1: General definitions and test 
requirements. 

I EC 68-2-1 : 1990, Environmental testing - Part 2: Tests - Tests A: Cold. 

lEC 68-2-2: 1974, Environmental testing - Part 2: Tests - Tests B: Dry heat. 



I EC 68-2-3: 1969, Environmental testing - Part 2: Tests - Test Ca: Damp heat steady 
state. 

lEC 68-2-6: 1982, Environmental testing - Part 2: Tests - Test Fc and guidance: Vibration 
(sinusoidal). 

lEC 68-2-14: 1984, Environmental testing - Part 2: Tests - Test N: Change of tempe- 
rature. 

lEC 68-2-27: 1987, Environmental testing - Part 2: Tests - Test Ea and guidance: Shock. 



lEC 68-2-30: 1980, Environmental testing - Part 2: Tests - Test Db and guidance: Damp 
heat, cyclic (12 + 12-hour cycle). 

lEC 68-2-31: 1969, Environmental testing ~ Part 2: Tests - Test Ec: Drop and topple, 
primarily for equipment-4ype specimens. 



15 



IS/IEC 1131-2(1992) 

lEC 68-2-32: 1 975, Environmental testing - Part 2: Tests - Test Ed: Free fall. 

I EC 85: 1984, Thermal evaluation and classification of electrical insulation. 

I EC 112: 1979, Method for determining the comparative and the proof tracking indices of 
solid insulating materials under moist conditions. 

I EC 255-4: 1976, Electrical relays - Part 4: Single input energizing quantity measuring 
relays with dependent specified time. 

I EC 364-4-443: 1990, Electrical installations of buildings - Part 4: Protection for safety - 
Chapter 44: Protection against overvoltages - Section 443: Protection against 
overvoltages of atmospheric origin or due to switching. 



I EC 417: 1973, Graphical symbols for use on equipment - Index, survey and compilation 
of the single sheets. 

I EC 445: 1988, Identification of equipment terminals and of terminations of certain 
designated conductors, including general rules of an alphanumeric system. 

lEC 529: 1989, Degrees of protection provided by enclosures (IP Code). 

lEC 664: 1980, Insulation co-ordination within low-voltage systems including clearances 
and creepag& distances for equipment. 

I EC 695-2-1: 1980, Fire hazard testing - Part 2: Test methods - Glow-wire test and 
guidance. 

I EC 707: 1981, Methods of test for the determination of the flammability of solid electrical 
insulating materials when exposed to an igniting source. 

lEC 801-2: 1991, Electromagnetic compatibility for industrial-process measurement and 
corrtrol equipment- Part 2: Electrostatic discharge requirements. 



lEC 801-3: 1984, Electromagnetic compatibility for industrial-process measurement and 
control equipment - Part 3: Radiated electromagnetic field requirements. 



lEC 801-4: 1988, Electromagnetic compatibility for industrial-process measurement and 
control equipment- Part 4: Electrical fast transient/burst requirements. 



lEC 801-5: 199X, Electromagnetic compatibility for industrial-process measurement and 
control equipment- Part 5: Surge immunity requirements (under consideration). 



lEC 947-1 : 1988, Low-voltage switchgear and controlgear - Part 1: General rules. 

lEC 947-5-1: 1990, Low-voltage switchgear and controlgear - Part 5: Control circuit 
devices and switching elements - Section One: Electromechartical control circuit devices. 

16 



IS/IEC 1131-2(1992) 



lEC 947-5-2: 1992, Low voltage switchgear and controlgear 
devices and switching elements - Section 2: Proximity switctyes. 



Part 5: Control circuit 



lEC 950: 1991, Safety of information technology equipment, including electrical business 
equipment. 

ISO/IEC 9506-1, 1990: Industrial automation systems - Manufacturing Message Specifi- 
cation - Part 1: Service definition. 

ISO/IEC 9506-2: 1990, Industrial automation systems - Manufacturing Message Specifica- 
tion - Part 2: Protocol specification. 

2 Service conditions and physical environment related requirements 

2.1 Normal service conditions 

It is the user's responsibility to ensure that the following service conditions are not 
exceeded. 

2.1.1 Physical environmental conditions 

2.1.1.1 Operating ambient air temperature 

Operating temperature ranges are given by the following table 1 . 

Table 1 - Operating ambient air temperature of PC-systems C'C) (note 1) 



Enctosed equipment 
(ventilated/non-ventilated) 



Open equipment 
(note 2) 



Type of 
limit 



Permanent 
installation 



Non-permanent 
installation 



Permanent 
installation 



Non-permanent 
installation 



Temperature 
range 



Max. 
Min. 



40 
5 



40 
5 



55 
5 



Average temperature 
over 24 h 



Max. 



35 



35 



50 



7. (note 3) 



NOTES 

1 See definitions in 1 .4.50 and in annex A. 

2 Open equipment is designed to be mounted within an enclosure where the equipment 
ambient air temperature which is measured immediately below each individual assembly may 
be up to IS "C above the maximum room ambient air temperature. 

No forced external cooling is assumed (seia 4.5.1). 

Open peripherals which are intended to be permanently installed as part of the PC-system shall 

meet the operating temperature range of the PC. 

3 Equipment ambient air temperature limits (7"_._ . r.„, T^i.) for open peripheral equipment 
not intended to be permanently installed shall be specifFed by the jnanufacturer. 



17 



IS/lEC 1131-2(1992) 

2.1 .1 .2 Storage temperature 

The allowable temperature range is -25 ''C to +70 °C. 

2.1.1.3 Relative humidity 

The manufacturer may select one of the two following levels. 

Table 2 - Operating ambient air relative humidity (notes 1 and 2) 



Relative humidity severity level 


Relative humidity range 


RH-1 
RH-2 


50 % to 95 % 
5 % to 95 % 


NOTES 

1 Non-condensing. 

2 See 2. 1 .2.2 for electrostatic discharge requirements. 



2. 1 . 1 .4 Pollution degree 

The manufacturer shall specify the pollution degree for which the equipment Is suitable, 

2.1.1.5 Corrosion immunity 

Corrosion conditions vary widely depending on the application and it is not possible to 
specify normal conditions of use. In ease of severe service conditions, see 2.2. 

The manufacturer shall specify the corrosion immunity of the equipment according to 
lEC 68. 

2.1.1.6 Altitude 

The equipment shall be suitable for operation up to 2 000 m. 

2. 1 .2 Electrical service conditions and requirements 

2.1 .2.1 A.C. and d.c. mains power supply 
Refer to 3.2. 

2. 1 .2.2 Electrical noise conditions 

Electrical noise conditions vary widely and depend on the installation wiring and other 
installed equipment and its proximity to the PC-system. 

For the purpose o1 this standard, the minimum noise conditions to which the PC-system 
shall be immune are indirectly expressed by the requirements given in 3.9.1. 



18 



IS/IEC 1131>2(1992) 



For electrostatic discharge (ESD) the mantifacturer may select one of the severity levels of 
the foHowing table 3. Refer to lEC 801-2 for description of classes of installation. 



Table 3 - Electrostatic discharge service corxjitions 



ESD severity fevsis 
(coordinatec! with ralative humidity severity levels) {not«} 



Leve! RH-1 
Level RH-2 



Level eSD-3 
Level ESD-4 



Class of instalfatiort 
(according to lEC 801-2} 



NOTE - See table 2 for dafinilion of relative humidity »everity levels. 



2.1.2,3 Overvo/fape category. Controf of transient overvoltages 

The nature ot the instailation shall be such that overvoitage category li conditions shall not 
be exceeded. 

Transient overvoltages at the point o1 connection to the mains power supply shall be 
controlled not to exceed overvoltage category II, i.e. not higher than the inrtpuise voltage 
corresponding to the rated voltage for basic insulation. The equipment or the transient 
suppression means shall be capable of absorbing the energy In the transient. (See 
3.10.2.} 

2. 1 .2.4 Non-periodic overvoHages 

in the industrial environment, non-periodic overvoltage peaks may appear on mains power 
supply lines as a result of power interruptions to high energy equipment (e.g. blown fuse 
on one branch in .aS-phase system). This wilt cause high current pulses at relatively low 
voltage levels (approximately 2 x U^^^y). The user shall take the r)ecessary steps to 
prevent damage to the PC-system (e.g. by interposing a transformer). See lEC 1131-4 for 
additional Information. 



2. 1 .3 Mechanical service conditions and requirements 

Vibration, shock and free fall conditions vary widely depending on the instaHatlort and 
environment and are very difficult to specify. 

For the purpose of this standard, the service conditions are indirectly defined by the follow- 
ing test requirements which apply to fixed equipment as well as to unpackagerf portable 
and hand-held portable equipment (see exceptions In 2.1.3.2). They do not apply to 
equipment containing assemblies other than PC-systems and/or associated peripherals. 



Experience shows that equipment passing these tests are suitable tor industrial use on 
stationary Installations. 

2.1,3.1 Vibrations 
Immunity requirements are: 

19 



IS/IEC 1131-2(1992) 
Table 4 - Sinusoidal vibrations service conditions for PC-systems (notes 1, 2 and 3) 



Frequency range 
Hz 


Continuous 


Occasional 


l0 5/<57 


0,0375 mm amplitude 


0,075 mm amplitude 


57 5 /S 150 


0,5 9 constant acceleration 


1 ,0 g constant acceleration 


150 < f 


Not defined 


Not defined 


NOTES 




1 Applicable to each of three mutually perpendicular axes. 




2 Test according to lEC 68-2-6, test Fc. 




3^ The manufacturer shall specify the method of mounting portable and hand-held portable 
peripherals on the test equipment. 



2.1.3.2 Shocks 

Immunity requirements are: Occasional excursions to ^5 g, 11 ms, tialf-sine, in each of 
three mutually perpendicular axes (lEC 68-2-27). 



NOTES 



1 



Devices containing CRTs are excluded from this requirement. 



2 Electromechanical relays may temporarily respond to 15 p shocks. Temporary malfunctioning is 
allowed during the test, but equipment should be fully functional after the test. 



2.1.3.3 Free falls 

Immunity requirements for type tests are: 



Table 5 - Free fall on concrete floor 
(Applicable to portable and hand-held portable equipment) 





Portable and hand-held 

portable 

(Any weight) 

(Withstand) 


Hand-held portable 

(Any weight) 
(Immunity) 


Noter 


Random drops 
Flat drops 
Supported drops 


100 mm; 2 trials 
30° or 100 mm; 2 trials 


1 000 mm^ 2 trials 


1 and 2 

1 
1 and 3 


NOTES 

1 Caution: Temporary malfunctioning is allowed at the impact, but equipment shall be fully func- 
tional after the test and not cause a shock hazard. Therefore-, if equipment is operating during the 
fall, erroneous operation could be introduced upon impact which may require operator correction. 

2 From prescribed altitude (normal position of use) see lEC 68-2-32, Procedure 1. 

3 From prescribed values given in 3.2.1 of lEC 68-2-31. 



20 



IS/IEC 1131-2(1992) 



2.2 Special service conditions 



When the service conditions are more severe than those given in 2.1, or other adverse 
environmental conditions exist, (e.g. air pollution by dust, smoke, corrosive or radioactive 
particles, vapours or salts, attack by fungi, insects or small animals), the manufacturer 
should be consulted to determine suitability of the equipment or the steps to be taken. 



2.3 Requirements for transport and storage of modules and subassemblies 

The following requirements apply to PC-units placed within manufacturer's original packag- 
ing. Transport and storage of unpackaged portable equipment should not exceed the 
requirements of 2.1. 

When components are included in the equipment which have particular limitations (e.g. 
CMOS components, batteries, etc.), the manufacturer shall specify the arrangements to be 
made for transport and storage. 

2.3.1 Temperature 

The allowable temperature range is -25 ''C to +70 "C. See test procedure in 6.3.4.2. 

2.3.2 Relative humidity 

The relative humidity range is 5 % to 95 % (non-condensing). 

2.3.3 Atmospheric pressure 

The minimum atmospheric pressure for transportation shall be not less than 70 kPa 
(equivalent to 3 000 m altitude). 

2.3.4 Free falls 

IVrtrts/and requirements for PC-units within manufacturer's original packaging are given in 
table 6 below. After the test, they shall be fully functional and shall show no evidence of 
physical damage. See test procedure in 6.3.5.4. 



Table 6 - Free fall on concrete floor 
(Applicable to PC-units under manufacturer's original packaging) 



Shipping weight 

without packaging 

kg 


Random free fall 

drop height 

mm 


Number of falls 


< 10 

10 to 40 

>40 


1 000 
500 
250 


5 
5 
5 


NOTE - According to tEC 68-2-32, procedure 1. 



21 



IS/IEC 1131-2(1992) 

2.3.5 Other conditions 

The user should reach agreement with the manufacturer for any mechanical conditions 
that are not specified In this standard. 

2.3.6 Information to be provided by the manufacturer 

The manufacturer shall provide shipping and storing instructions. 

2.4 Transport and storage conditions of^ PC-systems incorporated 
in complete control assemblies 

These conditions are not part of this standard and therefore the manufacturer should be 
consulted. 

3 Electrical requirements 

NOTE - Functional requirements for PC-systems including those relating to basic and advanced functions 
of PADTs are given in 3.6. 3.7 and 3.8. 

3.1 General 

Atypical PC-system and its interfaces are shown In figure 1 below. 



22 



IS/IEC 1131-2(1992) 



Main processing unit 



Remote I/O station 



Peripherals 
{permanentty/non 
permanentiy) installed 



Memory 

ties) 

and 

Processing 

Unit(s) 


Input 
modules 


C 

E 


Output 
modules 


Commu- 
nication 

modules 



Power supply 



^ 
^ 



Limit of the scope of this standard 



Programmable 

controller 

system 

(PC - system) 




u/i 



,Jt^ 



u/i 



Serial 

data 

transmission 



Digital & analog 
inputs 



Digital & analog 
outputs 



3fd Party devices 
(computers, 
printers, 
temiiruls) 



Mains 
power supply 



Protective earthing 
Funciionnal earthing 



Interfaced devices and signals 



A m Interface for remote I/O stations. 

6 « Interface for peripherals (permanently/non permanently) installed. 

C > Interface for digital and analog input signals. 

D - Interface for digital and analog ouput signals. 

E - Serial or parallel interfaces for data communication with third party 
devices. 

F « Interface for incoming power supply. 

G m jrrterface for protective earthing. 

H m Optional interface for functionnal earthing. 



tEC 95*92 



Figure 1 - Typical interlace diagram of a programmable controller system 



23 



IS/IEC 1131-2(1992) 

3.2 A.C. and d.c. power supply 

3,2.1 Incoming power supply 

3.2.1 .1 Rated values and operating ranges 

Incoming power supplies to the PC-system and to the externally powered I/O modules 
shall be as shown in table 7 below: 

Table 7 - Rated values and operating ranges of incoming power supply 



Voltage 


Frequency 


Recommended use; R 


Notes 


Rated 


Tolerance 
Min. / Max. 


Rated 


Tolerance 
Min. / Max. 


Power 
supply 


I/O 
signals 


5 


a4Vd.c. 

48^V^.c. 


-15%/ +20% 
id 


- 


_ 


R 
R 


R 
R 


1 
1,2 


24 V a.c. 

48 V ac. 
120 Vac. 
230 V ac. 
400 V a.c. 


-15%/ +10% 
ki 
kl 
kj 
kl 


50 Hz or 60 Hz 
id 
id 
id 
id 


-5 % / +5 % 
id 
id 
id 
id 


R 
R 
R 


R 
R 


3 

3- 

3,4 

3,4 

3.4,6 


NOTES 

1 In addition to the voltage tolerances, a total a.c. component having a peak value of 5 % of the 
rated voltage is allowed. The absolute limits are 30/19,2 V d.c. for 24 V d.c. and 60/38,4 V d.c. for 
48 V d.c. 

2 See itent 5 of 3.3.1 .2 if type 2 digital inputs are likely^ to be used. 

3 A.C. voltage is in terms of the total r.m.s^. voltage values measured at the point of entry to the 
equipment. 

Total r.m.s. content of true harmonics (integral multiple of nominal frequency) less than 10 times 
nominal frequency may reach 10 % of the total voltage. Harmonic and other frequency content for 
higher frequencies may reach 2 % of the total voltage. However, to provide constant comparative 
results, the equipment shall be tested at the third harmonic only (10 % at and at 180° phase 
angle). 

The total content of harmonics of the power supply to the PC-system may be affected when the 
energy source output impedance is relatively high with regard to the input impedance of the 
PC-system power supply; sizing a dedicated power source such as an inverter for a PC-system may 
require an agreement between the user and the manufacturer. Use of line conditioner should be 
considered. See lEC 1131-4. 

4 These rated voltages are derived from lEC 38. 

5 For incoming voltages other than those given in the table such as 100 V a.c, 110 V a.c, 
200 V a.c, 240 V a.c. 380 V a.c or 110 V d.c. 125 V d.c, the tolerances given in the table and 
notes 1 and 3 apply. These voltage tolerances shall be used to calculate the input limits of 3.3.1.2, 
using the equations in annex B. 

6 Three-phase supply. 

7 For power supplies for analog l/Os. see item 5 of 3.4.1.2.3 and item 3 of 3.4.2.2.3. 



24 



IS/IEC 1131-2(1992) 

3.2. 1 .2 Voltage drops and interruptions 

1) For short disturbances of the supply as defined in table 8 below, the PC-system 
(including RIOSs and non-permanently installed peripherals, see 3.7) shall maintain 
normal operation. 

2) For longer interruptions oi the supply(ies), the PC-system shall either maintain 
normal operation or go to a predefined state and have a clearly specified behavior until 
normal operation is resumed. 

NOTE - Outputs and fast responding inputs energized by the same supply(ies) will respond to these 
power supply variations. 

Table 8 - Normal service conditions: Voltage drops and interruptions 







Interruption 
time 


Time interval 
between drops 


Low voltage 


D.C. supply 
A.C. supply 


Severity level PS1 
Severity level PS2 


S 1 ms 

< 10 ms 

5 0,5 period 
{note 1) 


^1 s 
^ 1 s 
i 1 s 


Any voltage 
under lower 
operational 
limit 
l^mint'^o^e2) 


NOTES 

1 Any arbitrary phase angle - (see test procedure in 6.3.7.2). 

2 t/„i„ is the U. at mtnimum tolerance in table 7. 

3 PS1 applies to PC-systems supplied by battery. 

PS2 applies to PC-systems energized from rectified a.c. supplies and/or long d.c. fines. 



3.2.1 .3 Non-periodic overvoltages 
See 2.1.2.4. 

3.2.2 Memory back-up 

Power back-up for volatile memories shall be capable of maintaining stored information tor 
at least 300 h under normal service conditions, and 1 000 h at a temperature not greater 
than 25 "C when the energy source is at rated capacity. (For power back-up needing 
replacement, the rated capacity is the value used to designate the procedure and time 
interval for replacement.) 



It shall be possible to change or refresh power back-up without loss of data in the backed- 
up portions of memory. (See also 2.3, 3.6.3 and 4.1 1 .) 

If a memory back-up battery is provided, a warning of low battery voltage shall be 
provided. 



25 



JS/IEC 1131-2(1992) 

3.2.3 Information to be provided by the manufacturer 

In addition to the requirements stated in clause 5, the manufacturer shall provide the 
following information: 

1) data to adow selection of a suitable power distribution network to provide specified 
voltage at each power utilization point. This information includes peak inrush, repetitive 
peak and steady-state r.m.s input currents under full load conditions; 



2) external terminal identification for power supply interfaces; 

3) typical example(s) for power supply system(s); 

4) special supply installation requirements, if any, for PC-systems energized through 
multiple power supplies or supply voltages and frequencies not included in 3.2.1.1; 

5) the effect of the following incorrect connections of power to the supply(ies): 

- reverse polarity; 

- improper voltage level and/or frequency; 

- improper lead connection; 

6) complete information on PC-system behaviour for typical power up/down 
sequences; 

7) data to allow evafuation of the maximum values of interruption time which do not 
affect the normal operation of any PC-system configuration; PS class (PS-1 or PS-2) of 
d.c. supplied devices; 

8) memory back-up time with respect to temperature and maintenance requirements; 



9) recommended time interval between replacement of energy sources, if applicable, 
and recommended procedure and subsequent effects on the PC-system. 



26 



IS/IEC 1131-2(1992) 



3.3 Digital l/Os 

The following figure 2 gives an illustration of definitions of some I/O parameters. 



Current sinking 
PC INPUT 



f 







^ 


1 

INPUT ! 








\ 


Z 


PS 




COMMON 1 


^ 


(REFERENCE)! 

1 










-- 




_E 









PC SYSTEM 



Current sourcing 
PC OUTPUT 



COMMON (REFERENCE) 



OUTPUT 



LOAD 



i E 

C: Output 

- Mechanical or static contact (e.g. dry relay contact, triac, transistor or^quivalent). 
E: Earthings 

- The earth shown are optional. 

- Earthings is dependent on national regulations and/or application needs. 

Z: tnput 

~ Input impedance. 

PS: External power supplies. 
NOTE - Some applications may use only one PS common to inputs, outputs, and PC-system. 



PS 



_E 

lEC 9SSI92 



Figure 2 - I/O parameters 

Digital l/Os shall comply with the following requirements: 

1) the PC-shall be provided with at least one type of input interface and one type of 
output interface among those defined respectively in 3.3.1, 3.3.2 and 3.3.3; 

2) digital inputs shall comply with the requirements of the standard voltage ratings 
given in 3.3.1. Non-standard voltage digital inputs should be In accordance with the 
design equation given in annex B; 

3) digital outputs shall comply with the requirements of the standard ratings given in 
3.3.2.1 for a.c. or 3.3.3.1 for d.c; 



4) it shall be possible to interconnect inputs and outputs by means of a correct 
selection of the above digital l/Os, resulting in proper PC-system operation. (Additional 
external load shall be specified by the manufacturer if necessary); 



5) it shall be possible to feed multi-circuit a.c. input modules from different phases 
and the modules shall then comply with the maximum voltage difference likely to occur 
between phases, or the user manual shall include a note indicating that all channels 
must be fed from the same phase; 



27 



IS/IEC 1131-2(1992) 

6) if a multi-channel a.c. circuit is intended for multi-phase use the circuit shall comply 
wJth the clearance and creepage distance requirements and the dielectric test 
corresponding to the voltage between phases. 

NOTES 

1 Current sourcing inputs and current sinking outputs which may be required for certain applications are 
not covered in this standard. Special care should be exercised in their use. (Where positive logic, current 
sinl<tng inputs and current sourcing outputs are used, any short-circuit to the reference potential and wire- 
breakage are interpreted by the inputs and loads as the 'off state'; on the other hand, for current sourcing 
inputs and current sinking outputs, earth faults are interpreted as the 'on state'.) (See figure 2), 



2 A PC-system may be offered with interfaces which are not covered in this standard, i.e., interfaces for 
TTL and CMOS circuits, etc. In such a case, the manufacturer's data shall give all relevant information to 
the user. 

3.3.1 Digital inputs (current Sinking) 

3.3.1 .1 Terminology (U/l operation regions) 

Figure 3 below represents graphically the limits and operating ranges which are used 
herein to characterize current sinking digital input circuits. 



Operating region consists of "on region", "transition region" and "off region". It is neces- 
sary to exceed both UT min. and /7min. to leave the "off region", and to exceed IH min. 
before UH min. to enter the "on region": all input U/l curves shall remain within these 
boundary conditions. The region below zero volts is a valid part of the "off region" for d.c. 
inputs only. 

The figure also presents a graphical illustration of the method explained in 3.3.1.5 for 
determination of compatibility between a 2-wire proximity switch (curve I: worst case at 
state 1, curve tl: worst case at state 0), and a given input impedance curve (curve III). 



28 



IS/IEC 1131-2(1992) 



mmmm. 



Ue max { ■- ' 



ue ■; 



} Ue mm \ "\ 



m^m^^^^^Wm 



♦ in 1 '"."""- 1 






"ON REGION" 

. Curve in .1 : 
INPUT impedance, state 1 

,-'' Curve I : 

.^^i'',,,!^ Proximity switch worst case at state 1 



,-*- 



jUHrriin'j . 



VJ- L ill I ll ' M w . J UHmin L .~ UT max — 

max.| p . ^^, ' ^ , ^ ... . > I I \ f I 

^fnmn \ ,V^' '-'- - \ TRANSmON REGION" \ jtTmax | 

nr— f-| Ai^'curveni.1 : INPUT .mpedarKe stateO ^^^^^"^^^^^-^^71 

I "-'"!?;J'^i Curven : Proximity switcfi. worst case at state OFF REGION" I "j "^ t 

5p- i^i^f ■ . I ► 



iSC 936192 



UHmax. and UHmin. are the voltage limits for the ON conditions (state 1) 

IH max. and UH min. are the current limits for the ON conditions (state 1) 

UTmax. and LTmin. are the voltage limits for the transition state (ON or OFF) 

/Tmax. and /Tmin. are the current limits for the transition state (ON or OFF) 

UL max. and UL min. are the voltage limits for the OFF conditions (state 0) 

IL max. and IL min. are the current limits for the OFF conditions (state 0) 

UL max. equals UL min. to IT mm. and equals LTmin. above /fmin. 

Uq, U^ max. and U^ min. are the rated voltage and its limits for the external power supply voltage 



- I. II, III. (a), (b). (c), A. B relate to the example described in 3.3.1.5. 



Figure 3 - L/// operathjn regions of current sinking inputs 



3.3.1 .2 Standard operating ranges for digital inputs (current sinf<ing) 



Current sinking digital inputs shall operate within the limits presented In the following 
table 9. 



29 



IS/IEC 1131-2(1992) 



Table 9 - Standard operating ranges for digital inputs (current sinking) 



ND: Not defined 



Rated 
voltage 


Rated 
fre- 
quency 

Hz 


Type 

of 

limit 


Type 1 limits (note 7) 


Type 2 limits (note 7) 


Notes 


State 


Transition 


State 1 


State 


Transition 


State 1 


UL 
V 


mA 


UT 
V 


IT 
mA 


UH 
V 


IH 
mA 


UL 
V 


IL 
mA 


UT 
V 


IT 
mA 


UH 
V 


IH 
mA 


24Vd.c.. 

48Vd.c. 

24 V a.c. 

48Va.c. 

lOOVax. 
110Va.c. 
120Va.c. 

200Va.c. 
230Va.c. 
240Va.c. 


50/60 
50/60 
50/60 

50/60 


Max. 
Min. 

Max. 
Min. 

Max. 

Min. 

Max. 
Min. 

Max. 
Min. 

Max. 
I^n. 


15/5 
-3 

34/10 
-6 

14/5 


34/10 


79/20 


164/40 



15 
ND 

15 
NO 

15 


15 


15 


15 



15 
5 

34 
10 

14 
5 

34 
10 

79 
20 

164 
40 


16 
0.5 

15 
0.5 

15 
1 

15 

1 

15 

1 

15 
2 


30 
IS 

60 
34 

27 
14 

53 
34 

79 

1.1 L/, 
164 


15 
2 

15 
2 

15 
2 

IS 
2 

15 
2 

15 
3 


11/5 
-3 

30/10 
>6 

10/5 


29/10 


74/20 


159/40 



30 
NO 

30 
ND 

30 


30 


30 


30 



11 
5 

30 
10 

10 
5 

29 
10 

74 
20 

159 
40 


30 
2 

30 
2 

30 
4 

30 
4 

30 
4 

30 
S 


30 
11 

60 
30 

27 
10 

53 
29 

i.n/„ 

74 

'•' ^n 
159 


30 
6 

30 
6 

30 
6 

30 
6 

30 
6 

30 

7 


1. 2. 4. 5 

1.2,4 

1.3 

1.3 

1.3.4,6 

1,3.4,6 


NOTES 

1 All logic signals are in positive logic. Open inputs shall be interpreted as state signal. Compatibility with 
2-wire proximity switches according to lEC 947-5-2 is possible with type 2 (see also note 3). See annex B for 
equations and assumptions used in developing values in this table and for additional comments. 

2 The given voltage limits include all alternating voltage components. 

3 Static switches may affect the total r.m.s. content of true harmonics of the inpursignals and therefore affect 
the compatibility of the input interface with proximity switches, especially for type 2, 24 V a.c. See 3.2.1.1 for 
requirements. 

4 Recommended for common usage and future designs. 

5 The minimum external power supply voltage for type 2, 24 V d.c. inputs connected to two-wire proximity 
switches should be higher than 20 V d.c. or UHmin. lower than 1 1 V to allow sufficient safety margin. 

6 As allowed by the current technology, and to encourage the design of single input modules compatible with 
all commonly used rated voltages, limits are absolute and independent of rated voltage (except UH max.) and 
based on equations given in annex B and respectively 100 V a.c. and 200 V a.c. 

7 See definitions in 1.4.25. 



30 



IS/IEC 1131-2(1992) 



3 .3 . 1 .3 Additional requirements 



Each input channel shall be provided with a lamp or equivalent means to indicate the 
state 1 condition when the indicator is energized. 

3.3.1 .4 Information to be provided by the manufacturer 

[n addition to the requirements of clause 5, the manufacturer shall provide the following 
information: 

I) volt-ampere curve over the full-operating range, with tolerances or equivalent; 
2} digital input delay time (TID) lor to 1 and 1 to transitions; 

3) existence of common points between channels; 

4) effect of incorrect input terminal connection; 

5) isolation potentials between channel and bus and between channels under normal 
service conditions; 

6) type of input (type 1 or type 2); 

7) monitoring point and binary state of visual indicator; 

8) effects when withdrawing/inserting Input module under power; 

9) additional external load when interconnecting inputs and outputs, if needed; 

10) explanation of signal evaluation (for example static/dynamic evaluation, interrupt 
release, etc.); 

II) recommended cable and cord lengths depending on cable type and electro- 
magnetic compatibility; 

12) terminal arrangements; 

13) typical example(s) of external connections. 

3.3.1.5 Method for determination of compatibility with proximity switches 
For a given proximity switch, the following characteristics shall be identified: 

I) when at state 1: 

a) U^ ■ maximum voltage drop at state 1 

b) /j^Qi^: minimum output current load at state 1 
r. worst case output curve at state 1 

ii) when at state 0: 

c) /,gg,^: maximum output current at state 
II: worst case output curve at state 0. 

A given proximity switch shall be compatible with a given standard input (curve III: 
Impedance curve of the input) if: 

- its curves I and II do not enter the "transition region", and 

- Its /(^Qi^j is smaller than IH min. 

31 



IS/tEC 1131-2(1992) 

Worst case steady states and 1 shall be respectively at points A and B (at crossings of 
III with II and I). 

NOTE - This method may be used for any other type of static switch, such as outputs, etc. 



3.3.2 Current sourc'mg digital outputs for alternating currents 

3.3.2.1 Rated values and operating ranges (a.c. r.m.s.) 

Digital a.c. outputs shall comply with the ratings given in the following table 10, at the out- 
put voltage(s) stated by the manufacturer according to 3.2.1.1 and lEC 947-5-1, utilization 
category AC-15. See item 9 of 3.3.2.3, for other utilization categories. 

Table 1 - Rated values and operating ranges for current sourcing digital a.c. outputs 



Rated current (state 1) 


/e(A) 


0,25 


0.5 


1 


2 


Notes 


Current range for state 1 
(continuous at max. voltage) 


Min. (mA) 
Max. (A) 


10 [51 
0,28 


20 
0.55 


100 

1,1 


100 

2.2 


1. 2 


Voltage drop (state 1) 

- Non-protected output 

- Protected and short-circuit proof 


Max. (V) 
Max. (V) 


3 
5 


3 
5 


3 
5 


3 
5 


1 


Leakage current (state 0) 

- Solid state outputs 

- Electromechanical outputs 


Max. (mA) 
Max. (mA) 


5 13] 
2.5 


10 
2,5 


10 
2,5 


10 
2.5 


1 
2,3 


Repetition rate for temporary 
overload 

- Solid state outputs 

- Relay based outputs 


Operating 
cycles/min 

Min. 
Min. 


60 
6 


30 
6 


30 
6 


30- 
6 


4 


NOTES 















1 R.M.S. currents and voltages. 

2 Figures between ( ] apply to module not equipped with RC network or equivalent surge sup- 
pressors. All other values apply to modules with suppression. 

3 Leakage current for solid state outputs greater than 3 mA imply the use of additional external 
loads to drive type 2 inputs. 

4 Typical waveform for temporary overloads ('normal conditions of use') are shown in figure 4. 
The test method given in lEC 947-5-1 applies to solid state outputs for "normal conditions of use* 
except that the repetition rate shall be as given in the table. For 'abnormal conditions of use", the 
requirements given in lEC 947-5-1 apply. 



32 



IS/I EC 1131-2(1992) 



Currents (A) 

4 



101 



e 



rated line frequency) 
"ON" time) 



ti : 2 cycles at Fn (Fn 
t2 . : "ON- time 
t3-t2 : "OFF" time ("OFF" time 
t3 : Operation time 

• Relay OUTPUT • Solid state OUTPUT 

0,25 A 1 to 5 A 

t3-10s t3-1s t3-2s 




t3 



time (s) 
2£c snm 



Figure 4 - Temporary overload waveform for digital a.c. outputs 
NOTE - in lEC 947-5-1. the curve shown in figure 4 is named 'AC-15, normal conditions of use*. 

3.3.2.2 Additional requirements 
Output indicators 

Each output channel shall be provided with a lamp or equivalent means to indicate the 
output state 1 condition when the indicator is energized. 

Protected outputs 

For outputs stated by the manufacturer to be protected: 

1) the output shall either withstand and/or the associated protective device shall 
operate to protect the output for all steady state values of output current greater than 
1 ,1 times the rated value; 

2) after resetting or replacement of the protective device alone, as applicable, the PC- 
system shall return to normal operation; 

3) during any overload, there shall be no evidence of risk of fire or electrical shock, 
and immediately after any overload, the maximum temperature rise of the I/O insulation 
shall not exceed the value specified in 4.4.2. 

Optional restart capabilities may be selected among the three following types: 

i) automated restart protected output: a protected output which automatically 
recovers after the overload is removed; 

ii) controlled restart protected output: a protected output which is reset through 
signals (e.g. tor remote control); 

iii) manual restart protected output: a protected output which implies a human action 
to recover, (the protection may be fuses, electronic interlocks, etc.). 
See test procedure in 6.3.8.3.2. 



33 



IS/IEC 1131-2(1992) 

NOTES 

1 Operation under overload condition for an extended period of time may affect operating life of the 
module. 

2 Tfie protected outputs wilt not necessarily protect the external wiring. It is the user's responsibility to 
provide that protection when it is needed. 

Short-circuit proof outputs 

For outputs stated by the manufacturer to be short-circuit proof: 

4) For all output currents greater than /^ max. and up to 2 times the rated value 1^, the 
output shall operate and withstand temporary overload(s). Such temporary overload(s) 
shall be specified by the manufacturer. 

5) For all output currents prospectively above 20 times the rated value, the protective 
device shall operate. After resetting or replacement of the protective device alone, the 
PC-system shall return to norntal operation. 



6) For output currents In the range of 2 times to 20 times l^, or for temporary over- 
load(s) beyond the limits specified by the manufacturer (item 1 above), the module may 
require repair or replacement. 

7) During an overload of 2 /^ applied for 5 min, ttiere shall be no evidence of risk of 
fire or electrical shock and immediately after the overload, the maximum temperature 
rise of the I/O insulation shall not exceed the value specified in 4.4.2. 



See test procedure in 6.3.8.3.2. 



Not-protected outputs 

For outputs stated by the manufacturer to be not-protected, their operation with the pro- 
tective devices provided or specified by the manufacturer shall meet all the requirements 
stated for the short-circuit proof outputs. 



Electromechanical relay outputs 

Electromechanical relay outputs shall be capable of performing at least 0,3 million oper- 
ations at the AC-15 utilization category (durability class 0.3) according to lEC 947-5-1. 

NOTE - The type test is not required if the relay components have lieen shown to comply with the require- 
ments of lEC 947-5-1. 

3.3.2.3 Information to be provided by the manufacturer 

In addition to the requirements of clause 5, the manufacturer shall provide the following 
Information with respect to digital outputs for a.c. operation: 



34 



IS/IEC 1131-2(1992) 

1) type of protection (i.e. protected, short-circuit proof, not-protected output) and: 

-for protected outputs: operating characteristics beyond 1.1 /^ including the 
current{s) level(s) at which the protecting device energizes, the current behaviour 
beyond, and the time{s) involved; 

- for short-circuit proof outputs: information for replacement or resetting the pro- 
tective device as required; 

- for not-protected outputs: specification for protective device to be provided by the 
user, as required; 

2) output delay time (TQD) and output transfer times (TQT) for state to state 1 and 
state 1 to state transitions; 

3) commutation characteristics and turn-on voltage with respect to zero voltage 
crossing; 

4) existence of common points between channels; 

5) terminal arrangements; 

6) typical example(s) of external connections; 

7) number and type of outputs (e.g. NO/NC contacts, solid state, individually Isolated 
channels, etc.) ; 

8) for electromechanical relays, the rated current and voltage of the contacts for 
utilization category AC-15 and durability class according to lEC 947-5-1 and their 
mechanical life; 

9) output ratings for the other utilization categories (AC-12, AC-13, AC-14) or other 
loads such as Incandescent lamps; 

10) total output current for multichannel modules (see definition in 1 .4) ; 

11) characteristics of suppressor networks incorporated into the output circuit against 
voltage peaks due to Inductive kickback; 

12) type of external protective networks, if required; 

13) effects of incorrect output terminal connection; 

14) insulation/potentials under normal service conditions between circuits and bus 
and between circuits; 

15) monitoring points of visual indicators in the channel (e.g. MPU side/load side); 

16) recommended procedures for changing output modules; 

17) output behaviour during interruptions of MPU control, voltage drops and inter- 
ruptions and power up/down sequences (see also 3.6) ; 

18) way of operation (I.e. latching/non-latching type); 

19) effects of multiple overloads on multi-circuit modules. 

3.3.3 Current sourcing digital outputs for direct current 

3.3.3.1 Rated values and operating ranges 

Digital outputs shall comply with the ratings given in the following table 1 1 , at the output 
voltage(s) stated by the manufacturer according to 3.2.1,1 and with lEC 947-5-1 for 
utilization category DC-13. 

35 



IS/IEC 1131-2(1992) 



Table 1 1 - Rated values and operating ranges for current sourcing digital d.c. outputs 



Rated current (state 1 ) 


/e (A) 


0.-1 


0.25 


0.5 


1 


2 


Notes 


Current range for stage 1 at 
maximum voltage (continuous) 


Max. (A) 


0.12 


0.3 


0,6 


1.2 


2.4 




Voltage drop 
Not-protected output, 
protected and short-circuit 
proof 


Max. (V) 


3 
3 


3 
3 


3 
3 


3 
3 


3 
3 


1 


Leakage current (state 0) 


Max. (A) 


0.4 


1 


2 


2 


4 


2 


Temporary overload 


Max. (A) 


According to manufacturer's specifications 




NOTES 

1 For 1 A and 2 A rated currents, if reverse polarity protection is provided, a 5 V drop is allowed. 
This makes the output incompatible with a type 1 input of the same voltage rating. 

2 The resulting compatibilities between d.c. outputs and d.c. Inputs, without additional external 
load, are as follows: 

Rated output current /g (A): 0,1 0,25 0.5 1 2 
Type 1 : yes no no no no 
Type 2: yes yes yes yes no 

With adequate additional external load, all d.c. outputs may become compatible with all type 1 and 
type 2 d.c. inputs. 



3.3.3.2 Additional requirements 

Other requirements ar^ 4he sarrte as for current sourcing outputs for a.c. as defined in 
3.3.2.2, except: 

- for protected outputs: the limit is 1 ,2 /^ instead 1,1 /^ 

- for electromechanical relay outputs: AC-15 is replaced by DC-13. 

3.3.3.3 Information to be provided by ttie manufacturer 

Information to be provided by the manufacturer for digital outputs for d.c. shall be the 
same as for digital outputs for a.c, as defined in 3.3.2.3, except that the specification of 
commutation for zero voltage crossing does not apply, and AC-12, AC-13, AC-14 are 
replaced by DC-12 and DC-13. 



36 



IS/1EC 1131-2(1992) 

3.4 Analog t/Os 

3.4.1 Analog inputs 

3.4.1.1 Rated values and Impedance limits 

Rated values of signal range and imp&dance for analog inputs to PC-systems shall be as 
specified in the following table 12. 

Table 12 - Rated values and irripedance limits for analog Inputs 



Signa) range 


!nput impedance limits 


Notes 


-10 V. +10 V 


£10WI 




OV, +10V 


;?iokn 




IV. +5V 


£5kfi 




4 mA, 20 mA 


i300Q 




mA, 20 mA 


S300Q 


1 


NOTE 




1 Not racom-Tended for future designs. 





Analog inputs may be designed to be compatible with standard thermocouples or standard 
resistive temperature devices (RTDs) such as 100 Q Pt sensors. Thermocouple analog 
inputs shall provide a built-in cold-junction compensation. 



37 



IS/I EC 1131-2(1992) 



3.4.1.2 Information to be provided by the manufacturer 

Table 13 - Analog inputs: information to be provided 



3.4.1.2.1 Static characteristics 


Units and examples 


1) Input impedance in signal range 


a 


2) Analog input error 




- Maximum error at 25 °C 


± % of full scale 


- Temperature coefficient 


± % of full scale/K 


3) Maximum error over full temperature range 


1 % of full scale 


4) Digital resolution 


Number of bits 


5) Data format returned to the application program 


Binary, BCD, etc. 


6) Value of LSB (least significant bit) 


mV. mA 


7) Maximum permanent allowed overload (no damage) 


V, mA 


8) Digital output reading under overload condition 


e.g. flag 


9) Type of input- 


e.g. differential 


10) Common mode characteristic {d.c. 50 Hz, 60 Hz) if applicable 


CMRR-dB. CMV-V 


11) For other inputs (thermocouples, RTD. etc.) 




- type(s) of sensor(s) 


J, K, T, etc.: Pt 100, etc. 


- measurement range(s) 


Min. "C to Max. "C 


- linearization method 


Internal or 


' 


user-provided 


3.4.1.2.2 Dynamic characteristics 


Units and examples 


1) Total input system transfer time (TAID + TAIT) 


ms 


2) Sample duration time (including settling time) 


ms 


3) Sample repetition time 


ms 


4) input filter characteristics 




- order 


First, second, etc. 


- transition frequency 


Hz 


5) Maximum temporary deviation during each specified 




electrical noise test 


± % of full scale 


3.4.1.2.3 General characteristics 


Units and examples 


1) Conversion method 


Dual slope, S.A., 

etc. 
Trig, self-scan, 

etc. 
RC, opto-isolator, 


2) Operating modes 


3) Type of protection 




MOVs, etc. . 


4) Isolation potentials under normal service conditions 




between channel and a) bus, b) other channels, 




c) power supply(ies) interface(s) 


V 


5) External power supply data, if required 


Technical data 


6) Common points between channels if any 




7) Type, length of cable, installation rules 


Twisted pair, 50 m max. 


recommended to provide noise immunity 




8) Calibration or verification to maintain rated accuracy 


Month, years 


9) Terminal arrangements 




10) Typical example(s) of external connections 




1 1) Effect of incorrect input terminal connection 




3.4.1.2.4 Miscellaneous characteristics 


Units and examples 


1) Monotonicity with no missing codes 


Yes. no 


2) Crosstalk between channels at d.c, 50 Hz and 60 Hz 


dB 


3) Non-linearity 


% of full scale 


4) Repeatability at fixed temperature after specified stabilization time 


% of full scale 


5) Life time of electromagnetic relay multiplexors, if applicable 


Number of cycles, of fiours 



38 



IS/IEC 1131-2(1992) 

3.4.2 Analog outputs 

3.4.2.1 Rated values and impedance limits 

Rated values of signals range and load impedance for analog outputs of PCs shall be as 
specified in the following tabfe 14: 

Table 14 - Rated values and Impedance limits for analog outputs 



Signal range 


Load impedance limits 


Notes 


-10V+10V 


SlOCOfi 


1 


0V+10V 


sioooa 


1 


+1 V + 5 V 


k5ooa 


t 


4 mA, 20 mA 


S600C1 


2 


mA, 20 mA 


S600Q 


2.3 


NOTES 


1 Voltage analog outputs shall withstand any overload down to short 


circuit. 


2 Current analog outputs shall withstand any overload up to open 


circuit. 


3 Not recommended for future designs. 



3.4.2.2 Information to be provided by the manufacturer 

In addition to the requirements of clause 5, the manufacturer shall provide the following 
infoi'mation: 



39 



IS/IEC 1131-2(1992) 



Table 15 - Analog outputs: information to be provided 



3.4.2.2.1 Static characteristics 


Units and examples 


1) Output impedance in signal range 


n 


2) Analog output error 




- maximum error at 25 "C 


± % of full scale 


- temperature coefficient 


± % of full scale/K 


3) Maximum error over full temperature range 


± % of full scale 


4) Digital resolution 


Number of bits 


5) Data format in application program 


Binary. BCD, etc. 


6) Value of LSB (least significant bit) 


mV, mA 


3.4.2.2.2 Dynamic characteristics 


Units and examples 


1 ) Total output system transfer time (TAQD + TAQT) 


ms 


2) Settling time for full range change 


ms 


3) Overshoot 


% of full scale 


4) Maximum temporary deviation during electrical 


± % of full scale 


noise tests and test conditions 




3.4.2.2.3 General characteristics 


Units and examples 


1) Type of protection 


Opto-isolators, etc. 


2) tsolation potentials under normal service conditions between channel 




and a) bos, b) other channels, c) power supply(ies} interface(s) 


V 


3) External power supply data if required 


Technical data 


4) For current outputs with external supply, the maximum and minimum 




voltage drop across the output terminals in the full output range 


V 


5) Type, length of cable, installation rules recommended 




to provide noise, immunity 


Twisted pair, 50 m max. 


6) Calibration or verification to maintain rated accuracy 


Months, years 


7) Terminal arrangements 




8) Common points between channels if any 




9) Allowed type(s) of loads 


Floating, 




grounded 


10) Maximum capacitive load (for voltage outputs) 


pF 


11) Maximum inductive load (for current outputs) 


mH 


12) Typical examp(e(s} of external connections 




13) Output response at power up and power down 




14) Effect of incorrect output terminal connection 




3.4.2.2.4 Miscellaneous characteristics 


Units and examples 


1 ) Monotonicity 


Yes, no 


2) Crosstalk between channels at d.c, 50 Hz and 60 Hz 


dB 


3) Non-linearity 


% of full scale 


4) Repeatability at fixed temperature after specified stabilization time 


% of full scale 


5) Output ripple 


% of full scale 



40 



IS/IEC 1131-2(1992) 

3.5 Communication interfaces 

3.5.1 General requirements 

The configuration which shall be lested according to clause 6 of this standard shall be 
equipped with communication interface modules where applicable and with communication 
links specified by the manufacturer. 

Communication interface modules are subject to all general requirements relating to 
service conditions, mechanical construction, safety, markings, etc. (see in particular 2.1, 
3.8, 3.9 and clause 4). 

3.5.2 Information to be provided by the manufacturer 

If the manufacturer provides communication interfaces to other than his own equipment, 
he shall provide the necessary information for correct operation. This information shall 
include, but not be limited to. type of link, baud rates, energization of the line, type of 
cable to be used, isolation characteristics, protocols, character encoding, frame encoding, 
etc. 

3.6 Main processing unit(s) and memory (ies) of the PC-system 

NOTE - This subclause should be read in conjunction with lEC 1131-1 and with 3.7 and 3.8 of this part 
(respectively: RIOSs and peripherals). 

3.6.1 General 

See figu^re 1 In 3.1, and annex A for the definition and illustration of PC-system, main 
processing unit (MPU), main memory and other terms used in this subclause. 



3.6.2 Requirements 

Main processing unit(s) and memory(jes) are part of the permanent PC-instailation and 
therefore tested accordingly. They are subject to all general requirements relating to 
service conditions, mechanical construction, safety, markings, etc. (isee in particular 2.1, 
3.8,3.9,3.11 and clause 4) 

^.6.3 Information to be provided by the manufacturer 

1) organization, capacity of program memory; 

2) organization, capacity of data memory and number of bits per word; 

3) memory type(s) (i.e. CMOS-EPROM, etc.) available; 

4) memory back-up functionality and service requirements if any; 

5) data, constraints and procedures to determine a desired configuration (racks, 
cables, bus expanders, power supply unit, maximum number of l/Os per type, maximum 
number of I/O modules, etc.) 

6) description of the programming languages supported by the PC-system (combina- 
tion of the PADT and the main processing unit(s); 

7) to what extent the languages defined in lEC 1131-3 are supported, including the 
differences if any (objects, instructions, semantic and syntactic rules, etc.); 

41 



IS/lEC 1131-2(1992) 

8) calculation methods to determine- every memory utilization (user's application 
program and data, firmware program and data where applicable) and average, 
minimum and maximum value of every relevant time (scan tlme(s), system response 
time(s), transfer time(s), execution time(s)); 

9) mechanisms in which 1/Os are processed (i.e. use of I/O image registers perio- 
dically refreshed by the system, immediate "get/put" type instructions, interrupt and 
event-driven programs, etc.) and their effect on the following subjects: 

- system response time(s) ; 

- restart capabilities (I.e. cold, warm, hot restart) ; 

10) detailed times for inputs, outputs, processing, etc. 

11) effect of non-permanently installed peripherals on every relevant time (see item 8 
above) when they are plugged/unplugged, connected/disconnected to tlieir PC-system 
interface; 

12) PC-system status information concerning cold, warm and hot restart if applicable. 
Description and usage of programmable timers usable to determine the process- 
depende/it difference between warm and hot restart; 

13) test and diagnostic functions implemented (see 3.1 1) . 

3.7 Remote input/output stations (RIOSs) 

RIOSs are part of the permanent PC-installation and therefore to be tested accordingly. 
However, for ease of testing, isolated RIOSs may be tested separately where appropriate. 



3.7.1 Requirements 

1) Requirements for voltage drops and interruption of the power supply(ies) fully apply 
to RIOSs (see 3.2.1 .2). 

2) In case of loss of communication with the MPU application program, RIOSs shall be 
able to fix the states of their outputs to specified values, within specified delays and 
without passing through unspecified states and be capable of providing a fault 
indication signal. 

3) The MPU system shall provide the user's application program with relevant infor- 
mation on current status of RIOSs. 



3.7.2 Information to be provided by the manufacturer 

In addition to the requirements of clause 5. the manufacturer shall provide the following 
InformatioTi: 

1) specifications for the selection of adequate cables and other devices needed for 
the communication link; 

2) specifications for proper installation of the whole system (including proper 
selection of energy source(s)); 

3) type of I/O communication network (point to point, star, multidrop, ring, etc.) ; 



42 



IS/IEC 1131-2(1992) 

4) principles, procedures and transmission speeds used on the communication link 
and their capability to transfer data from and to the RIOSs witti respect to error 
coding/detection and to the delays of transmission in the best, most likely and worst 
oases; 

5) effect on transfer time(s) introduced to provide remote input information and 
RIOSs status to the user's application program and to transmit its logical decisions to 
remote outputs; 

6) specified values and delays according to 3.7.1 ; 

7) configuration related data: maximum number of RIOSs in one single PC-system 
configuration, min./max. size of each; 

8} which I/O modules of the total I/O system may not be used in RIOSs and/or which 
of their functions are altered if any; 

9) type, architecture and characteristics of redundancy if provided; 

10) modems/repeaters if applicable. Maximum distance with or without repeaters; 

11) terminating devices if required; 

12) physical characteristics of the communication interface including isolation charac- 
teristics, maximum acceptable common mode voltage, built-in short-circuit protections, 
etc.; 

13) type of standard link interface {i.e. RS 232, RS 422, RS 485, RS 511, etc.); 

14) functional and safety earthing specifications; 

15) procedures for making/breaking logical and physical connection of a BIOS to a 
PC-system (e.g. "on line") . 

3.8 Peripherals (PADTs. TEs. MMIs) 

3.8.1 Requirements 

1) Peripherals which are not a permanent part of the PC-system shall cause no 
malfunction of the system when making or breaking communication with an operating 
system. 

2) Connectors for the peripherals shall be polarized to prevent improper connection, or 
the PC-system shall be so designed that no malfunction occurs. 

3) The system consisting of the peripheral and the PC-system shall be designed to 
ensure that the edited program executing in the PC-system is functionaify identical to 
the edited program displayed on the peripheral. 

4) If on-line modification of the application program and/or the modes of operation of 
the PC-system by a peripheral is possible (i.e. when the PC-system is in active control 
of a machine or industrial process), then: 

- the peripheral shall automatically give clear warnings equivalent to "during on- 
line modification, program display may differ from application program, control of 
the machine/process may be interrupted during ... ms, etc.", as applicable, 



43 



IS/I EC 1131-2(1992) 

- the peripheral shall ask similar meaning words to "do you really want to carry out 
this action?" and execute the command only after a positive reply has been given by 
the operator, 

- it shall be possible to upload the new application program to the manufacturer's 
supplied data media and verify, on line, that the record is functionally equivalent to 
it, 

- means shall be provided to minimize unauthorized use of these functionalities 
(hardware or software). 

3.8.2 Information to be provided by the manufacturer 

1) Clear warnings and precautions to be observed when using functions enabling 
alteration of control conditions such as PC-system status modification, changing of data 
or programs In the memory, forcing input or output signal, etc. 

2) Usability of peripherals at RIOSs. 

3) Service conditions for peripherals which are intended for use in an environment less 
severe than stated in clause 2 (such peripherals may need to be remotely connected to 
the rest of the PC-system through communication lines). 

3.9 Noise immunity and emitted noise 

3.9.1 Electrical noise immunity requirements 

As receiving equipment, PC-systems are affected by interferences from conducted noise, 
radiated electromagnetic fields, and electrostatic discharges. General rules of installation 
which shall be followed to limit coupling factors and consequently interfering voltages at 
withstandable levels are noted in lEC 1131-4. 

The PC-system shall comply with the requirements in table 16. 

NOTES 

1 Conditions of use may require immunity to higher levels of electrical noise than the minimum given 
above. The manufacturer may select such higher values given in annex C. These higher levels shall be 
statiad by the manufacturer and the tests conducted according to these levels. 

2 The reference document for detailed tutorial and consideration is lEC 801. 



44 



IS/IEC 1131-2(1992) 



Table 16 - Electrical noise immunity requirements for PC-system 
and stand-alone peripherals (notes 1 ^nd 2) 



Electrical noise tests 


Electrical noise severity levels 


Notes 




Maximum surge 

energy 

Minimum source 

impedance 


All power 
supplies 


Digital l/Os 
t/g ^ 24 V 


Digital l/Os 
i/g < 24 V 

Analog, communi- 
cation l/Os 


Electrostatic discharge 

- For level RH-1:ESD-3 

- For level RH-2: ESD-4 

Radioelectromagnetic fietd 

Conducted noise 
Fast transient 
Common mode 

- Damped oscillatory wave 
Series mode 


150pF/150n 

4 mJ/spike at 2 kV 
on 50 a 

200 £2 


8kV 
15 kV 

10 V/m 

2kV 
1 kV 


8kV 
15 kV 

10 V/m 

1 kV 
1 kV 


8kV 
15 kV 

10 V/m 
0,25 kV 


3.4 

3 

3 
3,5 


NOTES 

1 Tests are perfornned on basic PC-system(s) (representative configuration{s) constituted by the PC 
configuration, and all peripherals that can be connected and which are intended for use under the normal 
service conditions). If peripherals are claimed to be on-line pluggable then the test procedure shall 
simulate on-line making/breaking of the physical peripheral conr>ectiOTi to the PC-system. When 
permanently installed, peripherals shall be placed in their 'monitor' mode or equivalent. (There is no 
requirement for simulation of operator's keying.) 

2 Tests are performed on operated peripherals providing stand-alone functions such as off-line docu- 
mentation, programming, compiling, editing, duplicating memory storages, etc. 

3 Analog l/Os and fast responding digital inputs may be affected temporarily during the disturbance but 
shall resume normal operation after the disturbance, and shall stay within the manufacturer's specified 
limits (see item 5 of 3.4. 1 .2.2 and item 4 of 3.4.2.2.2). 

4 Electrostatic discharges are applicable to all accessible conductive parts and insulating surfaces 
of the PC-system normally accessible to the operator such as switches, keyboards, module external 
packaging, shielding part of connectors etc. and to the protective and/or functional earth terminals, but 
not to the signal lines. 

5 Revision of these requirements is under consideration pending availability of lEC 801-5. 



3.9.2 Information to be provided by the manufacturer 

The manufacturer shall state if his peripherals are Intended to be used under normal 
service conditions or solely in a less severe environment (e.g. office environment). 

3.9.3 Emitted notse 

Due to differing national regulations, emission levels cannot be specified. Equipment shall 
meet the levels specified in every country of concern. 



45 



IS/IEC 1131-2(1992) 

3.10 Dielectric properties 

3.10.1 Generai 

Isolation may be provided for either safety (I.e. protection against electric shock) Or 
functional purposes (e.g. RFI immunity). Isolation requirements (clearance/creepage) for 
safety purposes are given in 4.3. 



3. 1 0.2 Dielectric withstand requirements 

1) Unless otherwise specified by the manufacturer, clearance and creepage require- 
ments of 4.3 shall be verified by mechanical measurement where possible. 

2) If mechanical measurement is not performed, the electrical test of 6.3.6.1 .1 shall be 
carried out. 

Exceptions: 

This test need not be done: 

- between isolated SELV circuits and accessible conductive parts (frames, 
enclosures, earth terminal, etc.); 

- on units (parts of the basic PC-system) which have been tested separately 
according to the relevant standards provided: 

a) the values given in table 17 below have been met, and 

b) their dielectric strength is not impaired by assembly; 

- between isolated circuits on printed wiring boards providing the specified 
clearances and creepage distances have been met. See 4.3. 

3) When subject to the dielectric test, insulation between isolated circuits other than 
SELV circuits and 

a) other non-SELV circuits, 

b) accessible conductive parts 

shall withstand the application of test voltage corresponding to their class and their 
rated voltage, as specified in table 17 below: 



46 



IS/IEC 1131-2(1992) 



Table 17 - Dielectric withstand voltages for impulse a.c. power frequency and d.c. tests 



RatedVoltage of circuit U 
V a.c. r.m.s. or V d.c. (note 2) 


Test voltages at 2 000 m (rote 1 ) 


For basic and supple- 
mentary insulation 


For reinforced insulation 
(note 3) 


Impulse, peak 
1,2/50 us 
(note 4) 


A.C- r.m.s. 


D.C. 
(note 4) 


<U^^ 50 

SO <U^i100 

100 <l/gi150 

150 <U^£300 

300 <y 5600 

6 


<U^< SO 

50 < Ug S 100 

100 <U^i 150 

150 <(;^S300 

300 <C/gS600 


500 
800 
1500 
2500 
4000 
6000 


350 
560 
1060 
1780 
2 830 
4230 


500 
800 
1500 
2500 
4000 
6000 


NOTES 

1 See annex 0: correction factor for testing at other altitudes. 

2 Rated voltage at the field wiring terminals of the device or circuit. 

3 Class (1 and applicable class 111 circuits. 

4 $66 6.3.6.1.1. 



NOTE - To recognize current practrces, the manufacturer may elect alternatively to verify the dielectric 
strength by the application of 2 U + 1000 V a.c, for a minimum duration of 1 min. 

4) When subject to the dielectric test, isolation between Isolated SELV circuits and 
other non-SELV circuits shall withstand the application during three cycles of 1500 V 
a.c. r.m.s voltage or Its equivalent peak value (i.e. 2 121 V) for the impulse or d.c. 
voltage, regardless of altitude. 

NOTE - Applicable national regulations shall be also considered for SELV circuits. 

5) When the assembly includes an equipotential conductor isolated from the access- 
ible conductive parts, it shall be regarded as an isolated circuit and shall be tested to 
the same voltage as the assembly to which it belongs. 

3.1 0.3 Information to be provided by the manufacturer 

In addition to the requirements of clause 5, the manufacturer shall provide the following 
information through convenient documentation and marking: 

1) rated isolation voltage and class of each PC-system subassembly; 

2) maximum permanent current withstandable by the Incorporated protective 
conductors and connections (see item 6 of 4.7.2). 



47 



IS/I EC 1131-2(1992) 

3.1 1 Self-tests and diagnostics 

3.11.1 General 

The manufacturer shall provide means of self-tests and diagnostics of the PC-system 
operation. Such means shall be built-in services of the PC-system, and/or recommended 
ways to implement the intended application. 

3.11.2 Requirements 

1) The following means shall be provided: 

a) a means for monitoring the user's application program (i.e. watchdog timer, 
etc.); 

b) a hardware or software means to check the memory integrity; 

c) a means to check the validity of the data exchanged between meTnory(ies), 
processing unit(s) and I/O modules; 

d) a means to check that internal voltages and currents delivered by the power 
supply unit(s) do not exceed the limits allowed by the hardware design; 

e) a means to monitor the status of MPU. 

2) The permanently installed PC-system shall be capable of operating an alarm signal 
on an alarm output. When the system is monitored as "functioning correctly" this alarm 
output shall be in a predetermined state; in the other case it shall go to the opposite 
state. The manufacturer shall specify the conditions of the "correct functioning state" 
and the self-tests which are executed to drive this alarm output; 

3) RIOSs shall be capable of operating an alarm signal on an alarm output (for 
example, ttirough a digital output module) in the event of loss of power ar loss of 
normal communication with the MPU and go to a predetermined state (see 3.7). 

3.11.3 Information to be provided by the manufacturer 

In addition to the requirements of clause 5, the manufacturer shall provide the following 
Information through convenient documentation and marking: 

1) description of tests and diagnostics which are implemented and when they are 
executed (i.e. permanently, periodically, upon user's application program request, 
during start-up procedure, etc.) ; 

2) correct functioning state and driving conditions of the alarm output(s) (see 3. 11 .2). 



4 Mechanical requirements 

4.1 General 

This section specifies mechanical construction requirements for PC-systems equipment 
(i.e. MPU, RIOSs, permanently/non-permanently Installed peripherals). Components 
connected to the mains power supply of the installation such as power supplies, I/O 
modules, communication interfaces, memory subsystems are considered subject to the 
provisions of this clause. 

48 



iS/lEC 1131-2(1992) 

The programmable controller equipment and the associated peripherals shall be 
constructed to withstand the conditions stated in clauses 2 and 3, 

4.2 Protection against electrical shock hazard 

1) Each entity of the PC-system shall be designed to meet class t, class \\ or ciass \\s 
specifications as defined \r\ 4.2.1, 4.2.2 or 4.2.3. 

2) Open equipment is not required to meet IP2X requirement. However, warning 
labels, hazard symbol 417-IEC-5036, and/or mechanical disconnect means shali be 
required on the final system enclosure to be provided bylhe user, to minimize the risk 
of accidental shock hazard during maintenance. Opening of the enclosure shall only be 
possible by means of a key or tool. 

3) Any class I or class II enclosed equipment shall be IP2X according to I EC 529. 

4) Apertures in class U equipment shall be tested with the test pin as specified in fig- 
ure 20 and ^.1 .2 of (EC 950. 

5) Leakage current of cord connected devices shall comply with the limits specified in 
lEC 950. 

MOTE - The tnsuSating propertw* ol lacquer, ©name!, ordinary paper, cottor, oxide film on metal parts and 
beads shaii not be relied upon to give the required prateclion against acc'tdental eont&ct with hazardous 
live parts. 

4.2.1 Cfass i equipment 

1) For equipment for use with a flexible cord (such as PADTs) this provision includes a 
protective conductor as part of the cordset (i.e. earth ground conductor). 

2) Some accessible conductive parts of a PC-system, which do not constitute a 
danger, need not be connected to the protective circuit of the PC-system. This applies 
to screws, rivets and namepiates. 

3) When a part of the PC-system is removed from the enclosure, for normal mainte- 
nance for example, the protective circuits serving the other parts of the PC-system 
shall not be interrupted. 

4) Protective earthing requirements are specified In 4.7. 

4.2.2 Cfass If equipment 

1) In certain cases such as signal level terminals (less than 30 V r.m.s.). limiting 
impedance may be used tn lieu of double insulation provided ihe limiting impedance 
limits the exposed terminals to a current of 5 mA and open circuit voltage of 30 V 
r.m.s.. or 42.4 V d.c. 

2) Class M equipment may be provided with means for maintaining the continuity of 
circuits (i.e. grounded internal components or conductive surfaces) provided that these 
circuits are double insulated from the accessible circuits of the equipment. 

3} Class II equipment may be provided with means for connection to earthing field 
terminals for functional purposes (such as radio frequency interferences suppression) 
provided the double insulation system is still provided for protective purposes. 



49 



rS/lEC 1131-2(1992) 

4.2.3 Class III equipment and safety extra low voltage (SEL V) circuits 

1} Isolation requirements between SELV circuits and the mains power supply are 
expressed in 3.10.2. 

2} Class III equipment may be provided with means for functional earth field wiring. 

3} Wiring for SELV circuits shall be either segregated from the wiring for circuits other 
than SELV. or the insulation of all conductors shall be rated for the higher voltage. 
AlternativeJy, earthed screening or additional insulation shall be arranged around the 
wiring for SELV circuits or around the wiring of other circuits. 



4.3 Clearance and creepage distances requirements 

1) The extent to which the manufacturing process can control the mechanical toler- 
ance decides the limits to which practical clearance and creepage distances can 
approach the theoretical minimum values given in the tables 18 to 24 of 4.3: 

- It is possible to approach minimum values when the equipment is manufactured 
In a factory under controlled conditions and finished to a point where additional 
assembly other than the connections to the field wiring terminals prior to placing the 
equipment in service is not necessary. 

- Replacement of components normally effected in service shops or in normal us« 
(e.g. fuses) are considered to be part of controlled conditions. Routine maintenance 
schedules for testing or examining insulation are expected. 

- Increased clearances are required when the equipment is field-mounted and 
field-connected because the method of mounting and the method of wiring at the 
field wiring terminals have to be considered, 

- In all cases the values given shall be met or exceeded. 

2) The actual clearance and creepage distances requirements will be based on the 
highest voltage and micro-environment specified by the manufacturer for each circuit. 

3} In place of the requirements for clearances and creepage distances expressed in 
4.3.1.1, 4.3.2 and 4.3.3, the values in the chart below that correspond to the current 
practice may be used for basic and supplementary insulation, up to pollution degree 2 
and regardless of CTI. In that case, no type test is required: compliance shall be 
verified by measurement. 



Rated voltage of circuit U. 
V a.c. r.m.s. or V d.c. 


Clearance 
mm 


Creepage distances 
mm 


< t/g 5 50 

50 < t/g S 300 

300 < t^g S 600 


1.6 
2.0 
4.8 


1.6 
3.2 
6.4 



50 



IS/IEC 1131-2(1992) 

4.3.1 Clearances relating to normal overvoltage category 

4.3.1.1 Clearances for other than field wiring terminals 

Clearances associated with basic and supplementary insulation and clearances asso- 
ciated with reinforced insulation (class II equipment) are given in table 18. They 
correspond to the impulse withstand voltage ot table 1-7 in 3.10.2. 



Table 18 - Minimum clearances in air corresponding to overvoltage 
category II conditions (except for field wiring terminals) 

(Derived from lEC 664) 



Rated voltage of circuit U 

(note 1) 

V a.c. r.m.s. or V d.c. 


Rated impulse withstand 

voltage (notes 2 and 3) 

V 


Minimum clearance 
mm 


For basic and 

supplementary 

insulation 


For 
reinforced 
insulation 


At 2 000 m altitude 


Pollution degree 
1 2 3 


<U^ < 50 

50 < L/g < 100 

100 <U^ < 150 

150 < Ug < 300 

300 < U < 600 
e 


< L/g < 50 

50 < ty„ < 100 
e 

100 < Ug < 150 

150 < U < 300 
e 

300 < L/g S 600 


500 
800 
1500 
2 500 
4 000 
6 000 


0,06 

0,12 

0,8 

2,0 

3,5 

6,5 


0,2 
0,2 
0,8 
2.0 
3,5 
6,5 


0,8 
0,8 
0,8 
2,0 
3.5 
6,5 


NOTES 

1 Rated voltage at the field wiring terminals of the device or circuit. 

2 See annex D; correction factor for testing at other altitudes. 

3 1.2 |j.s rise time; 50 \is wide at 1/2 amplitude; 0,6 J maximum energy. 



1) Clearances can be verified by mechanical measurement or by dielectric tests 
according to table 17 in 3.10.2. 

2) Clearances to walls of metal enclosures which may be deflected shall not be less 
than 12 mm. 

3) The above clearances do not apply to printed wiring boards with suitable protective 
coating. 

4) The above clearances do not apply to areas where Impulse voltages do not occur. 



4.3.1.2 Field wiring terminal clearances 

Minimum clearances at field wiring terminals from terminal to terminal and from terminal to 
enclosure shall comply with the requirements of table 19. 



51 



IS/IEC 1131-2(1992) 



Table 19 - Minimum clearances in air at field wiring terminals 



Rated voltage of circuit U 
V a.c. r.m.s. or V d.c. 


Termination clearances 
mm 


General case 


To walls of 

metallic enclosures 

which may be deflected 


< C/g S 50 

50 < C„ < 300 

300 < Ug ^ 600 


1.6 
3,2 
6.4 


12 

12 
12 



4.3.2 Clearances for micro-environment where the voltages are known and controlled 



In the case where the equipment is not connected directly to the mains and the peak 
voltages are known and controlled, the minimum clearances corresponding to these 
peak voltages are given in table 20. 

Table 20 - Minimum clearances in air for micro-environment 
where the voltages are Known and controlled 

(Definitions and entries in this table are derived from lEC €64) 



Peak voltage including all 
transients and impulses 


Minimum clearances 




V 


mm 




Up to 2 000 m altitude, 
(note) 


Pollution degree 
1 2 


3 


< Ug S 500 


0.06 


0.20 


0.80 


500 < U S 630 

e 


0.12 


0.20 


0.80 


630 < I/q S 800 


0,25 


0.25 


0.80 


800 < i/g 5 1 000 


0.40 


0,40 


0,80 


1 000 < i;^ s 1 200 


0.80 


0.80 


0,80 


1 200 < U^ 5 1 500 


1.2 


1,2 


1.2 


NOTE - See annex D: correction factor for testing at other altitudes. 



1) Clearances shall be verified by mechanical measurement. 

2) Clearances to walls of metal enclosures which may be deflected shall not be less 
than 12 mm. 



52 



IS/IEC 1131-2(1992) 



4.3.3 Creepage distances for basic and supplementary insulation 



Since creepage distances are at least equal to or greater than clearances, the actual 
values shall be selected to meet the requirements of both this subclause and subclauses 
4.3.1 or 4.3.2 as applicable. 

Table 21 - Classification of material group according to 
comparative tracking index (CTI)* 

(Definitions and entries in this table are derived from lEC 664} 



CTI 


Material group 


100 <Cr/< 175 
175 <Cr/< 400 
400 ^Cr/< 600 
600 < CTI 


lllb 
Ilia 
11 

1 


* See lEC 1 12, for ttie metfiod of determining CTI. 



4.3.3.1 Minimum creepage distances (basic and supplementary insulation) 

Minimum creepage distances given in this subclause are for a.c. r.m.s. or d.c. voltages 
which contain no impulse. For micro-environment where impulse voltage will be present 
(e.g. overvoltage category II or recurring peak voltages), other additional requirements 
apply. (See respectively 4.3.1 and 4.3.3.2.) 



4.3.3.1 .1 Minimum creepage distances for other than printed wiring boards 

Creepage distances shall be not less than values given in table 22 nor be less than the 
appropriate clearances. 



53 



IS/IEC 1131-2(1992) 



Table 22 - Minimum creepage distances in millimetres for 
other than printed wiring boards (note 1) 



(Definitions and entries in this table are from lEC 664) 







Creepage distances (note 4) 


Working voltage 

V a.c. r.m.s. or V dx. 

(not© 2) 


Pollution 

degree 

1 

(note 3) 


mm 


Pollution degree 2 


Pottutton degree 3 


Material group 


Material group 






1 l( llta, Itib 


1 II Ilia, (lib 


<U^ < 50 

6 


0,18 


0,6 


0,85 


1.2 


1.5 


1,7 


1.9 




50 < U^ i 100 
e 


0,25 


0.71 


1,0 


1,4 


1,8 


2,0 


2.2 


Basic and 


100 < U^ < 160 
e 


0,32 


0,8 


1,1 


1,6 


2,0 


2.2 


2.5 


supplementary 


160 < Wg S 320 


0.75 


1.6 


2,2 


3,2 


4,0 


4,5 


5,0 


insulation 


320 < Wg - ^^^ 


1.8 


3,2 


4,5 


6,3 


6,0 


9,0 


10.0 




630 < Wq S 1 000 


3.2 


5,0 


7,1 


10.0 


12.5 


14.0 


16,0 
(note 5) 




< Ug £ 50 


0,25 


0,71 


1,0 


1,4 


1,8 


2.0 


2.2 




50 <U^ < 100 

6 


0,42 


1.0 


1-4 


2,0 


2,5 


2,8 


3,2 


Reinforced 


100 <Uq < 160 


0,75 


1.6 


2.2 


3,2 


4,0 


4,5 


5,0 


insulation 


160 < U^ S 320 


1,8 


3,2 


4,5 


6.3 


8,0 


9.0 


10.0 




320 <U^ <. 630 


4.2 


6.3 


9,a 


12,5 


16,0 


18,0 


20,0 




630 <ygSiooo 


7.5 


10,0 


14,0 


20.0 


25,0 


28,0 


32,0 
(^ote 5) 


NOTES 


1 Creepage distances given in tfiis table are for a.c, r.m.s. or d.c. voltages which contain no impulses. For 
micro-environment where impulse voltages wilt be present, other additional requirements apply. 


for o^ervollage category II, the creepage distances shall be not less than the appropriate clearance 
distances values (see 4.3.1); 

- creepage (and clearance) distances of high frequency voltages generated in switch-mode power supplies 
shall be evaluated using table 24 in 4.3.3.2. 


2 V a.c. r.m.s. of sinusoidal or non-sinusoidal wave. 


3 For all material groups. 


4 Creepage (and clearance) distances between circuits shall be that corresponding to the highest worsting 
voltage and the corresponding dielectric withstand voltage. 


5 Only for material group Clla. Material group lllb is in general not recommended for application in pollution 
degree 3 above 630 V. 


6 Maximum recurring- peak voltages in normal operation shall be limited to the values in 4.3.3.2 to prevent 
degradation of insulation by partial discharges. 



54 



IS/IEC 1131-2(1992) 



4.3.3. 1 .2 Minimum creepage distances for printed wiring boards 

Creepage distances associated witli basic and supplementary insulation for protective 
coated and uncoated areas of printed wiring boards shall be not less than given in the 
table 23 below nor be less than the values of the appropriate clearances. 



Table 23 - Minimum creepage distances for printed wiring boards (notes 1, 6 and 9) 
(Basic and supplementary Insulation) 

(Definitions and entries in this table are from lEC 664) 



Circuit voltage 
V a.c. r.m.s. or V d.c. 

(note 2) 


Areas of PWBs 

with protective 

coating 

mm 

(notes 3. 4, 5 and 6) 


Uncoated areas of PWBs 
mm 


Pollution degree 1 
(note 7) 


Pollution degree 2 
(note 8) 


<U^< 50 

50 <U^S 100 

100 < Ug S 160 

160 <U^^ 320 
e 

320 < Wg £ 630 
630 < fg S 1 000 


0.025 

0,1 

0.25 

0,75 

1,8 

3,2 


0,025 

0.1 

0.25 

0.75 

1.8 

3.2 


0,04 

0.16 

0,4 

1.6 

3.2 

5 


NOTES 

1 Creepage distances given in this table are for a.c. r.m.s. or d.c. voltages which contain no 
impulses. For micro-environment where impulse voltages wilt be present, other additional require- 
ments apply: 

for installation category II, the creepage distances shall be not less than the appropriate 
clearance distances values (see 4.3.1); 

creepage (and clearance) distances of high frequency voltages generated in switch-mode power 
supplies shall be evaluated using table 24 in 4.3.3.2.2. 

2 V a.c. r.m.s. of sinusoidal or rron-sinusoidal wave. 

3 Protective coating shall adhere to the board insulation to result in an effectively solid insulation 
so as to exclude moisture and pollution and to withstand the specified overvoltages given in 3.10.2. 

4 Suitable for all material groups and pollution degrees 1 , 2 and 3. 

5 No test is required if the manufacturer provides evidence that the protective coating has been 
tested according to either the test given in 6.3.5.5.7 or an equivalent acceptable independent 
laboratory test. 

6 A test board, coated but without components, ^hatl withstand the appropriate dielectric test 
voltage given in 3.10.2. 

7 For all material groups. 

8 For material groups 1, II, Ilia. 

9 Creepage (and clearance) distances between circuits shall be those corresponding to the highest 
working voltage and the corresponding dielectric withstand voltage. 

10 Maximum recurring peak voltages in normal operation shall be limited to the values in 4.3.3.2 to 
prevent degradation of insulation by partial discharges. 



55 



IS/IEC 1131-2(1992) 

4.3.3.2 Creepage distance requirements for recurring peak voltages 

4.3.3.2.1 Rationale 

The phenomenon of partial discharges will occur on a surlace which is subjected to long 
periods of high humidity and recurring peak voltages (impulses). These recurring peaks 
will dry out small areas between the conductors which will then flash over, giving rise to 
small sections of tracking. Eventually total tracking will occur between conductors and 
breakdown occurs. The values given in the table 24 in 4.3.3,2.2 will prevent any partial 
discharge from occurring, and are vaiid for pollution degrees 1 to 3. 

4.3.3.2.2 Creepage distance requirements for recurring peak voltages 

In addition to the clearance and creepage distance requirements of the preceding clauses, 
when recurring peak voltages are present the creepage distance requirements given in 
table 24 below shall also be met. 



Table 24 - Minimum creepage distances related to recurring peak voltages 
on uncoated printed wiring boards (pollution degrees 1 to 3) 
(note 1) 



Maximum recurring 

peak voltage 

(note 2) 


Creepage distance 
mm 


Maximum recurring 

peak voltage 

(note 2} 


Creepage distance 
mm 


330 
400 
450 
600 
640 
800 


0.1 
0,2 

0.25 
0.4 
0.5 
0,75 


1 140 
1 150 
1250 
1650 
1 700 
2200 
2300 
2800 


1,5 
1,6 
1,8 
3.0 
3,2 
5,0 
5.5 
8,0 


NOTES 

1 This table does not apply to peak values of 50 Hz/60 Hz wave of tfie mains power supply 
(see 3.2.1.3). However, it does apply to short duration peaks superimposed on the 50 Hz/60 Hz 
wave. 

2 Recurring peak voltage values are based on statistical evaluation of partial discharge data. 



4.3.3.2.3 Example 

The following figure 5 shows which requirements apply to each part of a typical design of 
a power supply: 



56 



IS/IEC 1131-2 n992) 



O- 



LINE INPUT 
(120/230Va.c. r.m.s.) 
(50 / 60 Hz) 



a 



Zone 1 



SWITCH - MODE 
power supply 

(RECURRING VOLTAGE) 
(450 V, 1.6 kV) 



Zone 2 



-t> ' -ej- 



DC OUTPUT 
(SELV) 



Zone 3 



1.6 kV -• 



500 V ■■ 



500 V -■ 



-1,6kV -- 



Recurring peak voltage 



Working voltage 



-► t 



Working voltage 



Recurring peak voltage 

tec 9X192 



Zone 1: Creepage distance a 2,0 mm, controlled by minimum clearance for overvoltage category II, as 
given in table IB in 4.3.1.1. 

Zone 2: Creepage distance ^ 3,0 mm (pollution degree 1 assumed), controlled by recurring peak voltage, 
as given in table 24 in 4.3.3.2.2. 

Creepage distance i 3,2 mm (pollution degree 2 assumed), controlled by creepage distances for 
PWBs, as given in table 23, in 4.3.3.1.2. 

Zone 3: No requirements for SELV. 



Figure 5 - Creepage distances of circuits where recurring peak voltages 
are generated 



57 



IS/IEC 1131-2(1992) 

4.3.4 Creepage distances for reinforced insulation 

Creepage distances shall be double the value for basic insulation. 

4.4 Flammability requirements for insulating materials 

4.4.1 Non-metallic materials 

All non-metallic materials employed in the PC-system (i.e. printed wiring boards, plastic 
enclosures, wire insulation, etc.) with exceptions as noted below shall have suitable flame 
retardant properties to prevent or minimize the spread of flame and comply with a vertical 
flame spread rating of FV1 or FVO as given in clauses of lEC 707. 



No tests are required if the manufacturer provides evidence that the material complies 
with lEC 7QJ or alternatively the lEC 695-2-1 glow-wire test, under the conditions given in 
table 25 below. 

Table 25 - Flammability of non-metallic materials 
(Glow-wire test, see lEC 695-2-1) 





Test 

temperature 

"C 


Length of 

application 

s 


Extinguishing 

time 

s 


Live parts supports 


750 


30 


5 30 


Enclosures 


650 


30 


£30 



Exceptions^ 

1) Printed wiring boards: printed wiring board materials may have a flame rating of 
FV2 provided there is no combustible material less than 300 mm below the plane of the 
board. If the board is not manufactured with accompanying housing or enclosure, the 
board shall be rated FVI or FVO as above. 

2) Decorative material (cosmetic plastics): non-metallic materials used solely for deco- 
rative purposes (i.e. not for support of live parts or enclosure protection) require no 
special flame retardant additive. 



4.4.2 Temperature limits of materials 

The temperature rise limits as specified in the following table 26 shall not be exceeded by 
the equipment or parts defined in its complete system when tested at full load and under 
normal service conditions: 



58 



IS/IEC 1131-2(1992) 



Table 26 - Temperature rise limits (notes 1,3,4 and 5) 









Maximum temperature rise 

-c 




Open equipment 
(note 2) 


Enclosed equipment 
(note 2) 


Hand-held accessible devices 


Metallic 
Non-metallic 


5 
10 


15 

25 


Parts intended to be touched 
in normal t)peration 


Metallic 
Non -metallic 


15 
25 


30 
40 


Parts not intended to be touched 
in norma) operation 


Metallic 
Non-metalllic 


25 

(note 7) 

35 


40 

(note 7) 

50 


Terminals 
(note 6) 


Bare copper 


45 


60 


Bare brass/tin 

Piated copper and brass 


60 


65 


Silver or nickel plated 
Copper or brass 


55 


70 


NOTES 

1 Temperature rise limits are based on an ambient temperature given in 2.1.1.1. 

2 Open equipment and enclosed equipment are defined in 1.4. 

3 All other materials employed within the PC-system not covered in the table shall be in com- 
pliance with the relevant requirements for that particular component as based on a 55 °C ambient for 
open equipment and 40 °C for enclosed equipment. 

4 The maximum temperature for several classes of insulation is given in lEC 85. 

5 Enclosed units shall be tested with the maximum components mounted and energized. 

6 The terminals shall be wired with conductors of the minimum size stated by the manufacturer. If 
the manufacturer does not state wire sizes the minimum size in table 27 in 4.6.2.2 shall be used. 

7 Temperature rise limits may be exceeded if proper warning signs are provided. 



4.5 Enclosures 

4.5.1 Evaluation of enclosures for open equipment (power dissipation) 

The manufacturer's documents shall provide information to allow the evaluation of 
the power dissipation of every PC-configuration, sub-assembly and module and provide 
Information regarding minimum spacing required to assure adequate cooling under normal 
service conditions. 



59 



IS/iEC 1131-2(1992) 

4.5.2 Moving parts in non-portable devices 

Moving parts (e.g. fans, disk drives, printers, etc.) located within non-portable devices 
which could cause possible Injury to service personnel during routine maintenance shall 
be arranged or enclosed to provide protection against such injury. Protective guards, 
enclosures, control rooms or similar means should be considered. If such protective 
devices are not provided with the programmable control system, suitable installation 
instructions, warning labels, or the equivalent shall be provided to clearly indicate the 
user's installation requirements. 



4.5.3 Enclosures for portable equipment 

IVIechanical enclosures for portable equipment shall meet the general enclosure require- 
ment of I EC 950. 

4.5,3,1 Protection against access to hazardous live or moving parts 

Portable equipment shall provide on all outer surfaces degree of protection IP2X against 
contact with hazardous live or moving parts, according to lEC 529. This protection shall 
also be applicable with the service doors opened or covers of service openings removed. 



Class II portable equipment shall in addition prevent contact with bare parts at hazardous 
voltages and be tested by the application of the test pin defined in figure 20 of I EC 950 to 
all openings in the enclosure. 



Class III portable equipment only needs to be verified for protection against contact with 
moving parts, since SELV is not hazardous. 

4 .5 .3 .2 Shafts and knobs 

Shafts and knobs external to the enclosure shall not be in contact with hazardous live 
parts. If the parts are normally held or actuated in normal operation, the insulation 
provided shall be such ttiat the shafts artd knobs do not become live in the event of an 
insulation fault. 

4.5.3.3 Plug connections 

Portable equipment connected to the mains power supply by use of a cordset (removable 
or fixed) shall be so designed that there is no risk of electric shock from charged capa- 
citors when touching the pins of the plug and/or receptacle. 



4.5.3.4 Accessibility of live parts through their supporting surfaces 

Portable equipment shall be constructed so that all live parts shall be at a distance of at 
least 6 mm from any openings (measured vertically) In their supporting surfaces. 



60 



IS/I EC 113t-2(1992) 



4.5.3.5 Stability 



Equipment shall be constructed So that It operates in all positions to be expected in normal 
operation, and, does not become unstable when tipped in any direction 15° from the in- 
tended operating position. 

4.5.3.6 Mechanical strength 

The mechanical strength of the enclosure shall be such as to withstand rough handling in 
normal use. The protection provided by the enclosures shall be verified after the applica- 
tion of the standard lEC imoact test (see 4.2.4 of lEC 950). 



4.5.3.7 Flammability 

Non-metallic materials employed in the enclosure shall comply with the flammability 
requirements of 4.4.1. 

4.6 Terminal connection mechanical requirements 

NOTE - The applicability of the requirements of lEC 947-1 to this subclause is under consideration. 

4.6.1 Constructional requirements 

1} Terminals shall be so designed that loose strands of wire shall tiot reduce the 
required clearance/creepage requirements. 

2) All parts of terminals which maintain contact and carry current shall be of metal of 
adequate mechanical strength. 

vj; icTiiiiiiiai uuiiiic;v^iiuiid diiaii \jv ;>uuii tiidi iiic ^UMUUUii.;i:> may uc v>uiine\^teu uy 

means of screws, springs, or other equivalent means such as wire wrap, terml-point, 
fast-on connection, clamp-type connection so as to ensure that the necessary contact 
pressure Is maintained over the full range of service conditions. 

4) Terminals shall not allow the conductors to be displaced or be displaced themselves 
in a manner detrimental to the operation of the equipment and the insulation shall not 
be reduced below the rated values. 

5) The mechanical design of the interfaces shall allow that no elementary conductor is 
subjected to bending of a radius of curvature less than six times its diameter after 
removal of the common elements (armouring, sheaths, fillers). 

6) Clearances between wiring terminals and terminal to earthed parts are given in 
4.3.1.2. 

4.6.2 Connecting capacity 

4.6.2.1 General 

The wire sizing of the terminal shall be in accordance with local, and/or national electrical 
standards as applicable. Terminals shall be suitable for the wire size(s). number of wires, 
and type of wire (copper, aluminium, etc.) required for the intended application. See 
lEC 1131-4 for more information. 

4.6.2.2 Minimum requirements for field wiring terminals 

The following table 27 specifies the minimuin range of wire sizes which shall be properly 
accepted by the terminal with respect to the type of interfaces. 

NOTE • Stranded wires may be used if they are suitably terminated. 

61 



IS/IEC 1131-2(1992) 



Table 27 - Minimum range of wires sizes for field wiring terminals 



Type of interface 


Minimum- range of wire sizes 
mm* 


Low limit 


High limit 


Digital inputs 

Digital outputs 

Analog l/Os 

Communication 

Mains^ power supply (note) 

Protective earth (note) 


0.5 (AWG20) 
0.5 (AWG20) 
0.18 (AWG24) 
0.16 (AWG24) 
1.5 {AWG16) 
1.5 {AWG16) 


1,5 (AWG16) 
2.0 (AWG14) 
1,5 {AWG16) 
1,5 (AWG16) 
2.5 {AWG12) 
2,5 (AWG12) 


NOTE - The minimum size of the conductor for the connection to the mains power supply and 
protective earth is generally specified in the national wiring rules. 



4.6.3 Information to be provided by the manufacturer 

tn additioin to the requirements of clause 5, the manufacturer shall provide the following 
Information through convenient documentation and/or marking: 

1) type, cross-sectional area and material of the conductors tliat may be connected to 
the PC system; 

2) recommendations for use of shielded cables, and how they are to be connected and 
earthed. 



4.7 Provisions for protective earthing 

NOTE - The requirements specified below do not apply to SELV circuits where protective earthing is not 
required. 

4.7. 1 Constructional requirements: 

4.7.1 .1 Class I equipment 

1) The accessible parts (e.g. chassis, framework and fixed metal parts of metal 
enclosures) other than those which do not constitute a danger shall be electrically inter- 
connected and connected to a protective earth terminal for connection to an external 
protective conductor. This requirement can be met by the normal structural parts provid- 
ing adequate electrical continuity and applies whether the equipment is used on Its own 
or Incorporated in an assembly. 

2) Cords or cables that supply transportable peripherals shall be provided with a 
protective earthing conductor. 

3) Protective earthing conductor insulation shall be green with a yellow stripe. 

4) Accessible isolated conductive parts are considered not to constitute a danger if 
they are so located as to exclude any contact with live parts and withstand the 



62 



IS/IEC 1131-2(1992) 

dielectric test voltage of table 17 in 3.10.2 for reinforced insulation corresponding to 
1he highest rated operatronal voltage of the unit. 



4,7.1 .2 Class 11 equipment 

Class II equipment may have an internal functional bonding conductor but shall not be 
provided with an earthing terminal or an earthing conductor In the supply cord. 



4.7.2 Protective earthing terminal 

If the PC-system Is provided with a protective earthing terminal (class I equipment), the 
following requirements also apply in addition to the previous general connection speci- 
fications: 

1) the protective earthing terminal shall be readily accessible and so ptaced that the 
connection of the equipment to the protective earthing conductor is maintained when 
the cover or any removable part is removed; 

2) products which are intended for cord connected use (such as peripherals) shall be 
provided with a protective earthing terminal integral to the plug cap, or socket (if remov- 
able cordset); 

3) the protective earthing terminal shall be of the screw type and shall be made of 
brass or other suitable non-corrosive material; 

4) the clamping means of protective earthing terminals shall be adequately locked 
against accidental loosening and it shall not be possible to loosen them without ihe aid 
of a tool; 

5) protective earthing terminals and earthing contacts shall not be electrically 
connected to the neutral terminal at the PC-system. 

NOTE ' A terminal intended to be connected to the PEN (protective earth neutral) conductor may fulfil the 
function of the protective earthing terminal. 

6) the protective earthing terminal and subsequent protective equipment internal to the 
PC-system shall provide 0,1 fi protective earthing continuity under 30 A continuous 
fault conditkins; 

7} the protective earthing terminal shall have no other function. 

4.8 Functional earthing 

There are no constructional requirements such as noise Immunity control, RFI protection, 
etc., for functional earthing terminals (except for marking requirements as given In 
4.12.2.6). 

4.9 Interconnecting cables and cords 

4.9.1 General 

The following requirements shall apply to interconnecting cords or cables provided by the 
manufacturer for the internal and/or external wiring of PC-system. 

4.9.2 Wiring Internal to the PC-system (internal wiring) 

1) The insulation, when provided, on all internal wiring of the equipment shall be rated 
for the voltage and the temperature conditions of use. 

63 



IS/lEC 1131-2(1992) 

2) All splices and connections shall be mechanically secure and provide electrical 
continuity. 

3) Internal wiring shall be so routed and secured that neither it nor related electrical 
connections are likely to be subjected to stress or mechanical damage. 

4) Interna! wiring that is subject to flexing in its intended use or maintenance and 
whose conductOTS are solid or the insulation of which is less than 0,8 mm thick shall be 
tested for flexing integrity as specified in 6.3.5.5.4. This requirement does not apply to 
SELV circuits. 

4.9.3 Connectors and wiring external to the PC-system (external wiring) 

NOTE - This clause applies to the PC-system and the manufacturer supplied cables with connectors only 
and does not apply to the whole industrial control system in which the PC-system is employed. 

1) Cables and cords provided for the interconnection of open equipment shall comply 
with the requirements of 4.9.2. 

2) Cable assemblies and flexible cords provided for interconnection between sections 
of equipment or between units of a PC-system shall be a type that is acceptable for \he 
voltage and temperature involved and shall be provided with suitable strain relief. 

3) Misalignment of plug and socket connectors, insertion of a multi-pin connector In a 
connector other than the one intended to receive it and plugging and unplugging of 
connectors that are accessible to the operator shall not result in mechanical damage or 
risk of fire to the PC-system or electric shock or injury to persons from the PC-system. 



4) To prevent incorrect operation when making and breaking interconnections between 
portions of the PC-system either the connector socket shall be polarized to prevent 
improper insertion or the PC-system shall be designed so ttiat no malfunction occurs or 
the manufacturer shall provide clear instructions to the user on the actions to be taken 
when connecting or disconnecting. 

5) Protective earthing conductor insulation shall be green with a yellow stripe. 

4.9.4 Internal and external wiring 

Connectors shall be positioned so that wires and cables need not be routed over operator 
devices and their identification. 

4.10 Plugging/unplugging of removable units 

1/ IViUUUiai V'UnaiiuwiiUii ui rv^-^vfuipiiicm oiiv/uiu uc sjooi^msu iw ■■^■■iiiiiiii.o v<«iii«yw tv 

PC-system, when inserting or removing modules. Modules of the same type or family 
and accordingiy marked shall be interchangeable when de-energlzed. Adjustments or 
setting of parameters such as address, threshold, gain, and data transmission speed 
may be required prior to using the new module in the intended operation. 



2) All units requiring plugging or unplugging during operation or maintenance shall 
withstand the number of insertions and withdrawals given in table 28 without adverse 
effect on their contact making effectiveness. 

64 



IS/lEC 1131-2(1992) 



Table 28 - insertion/withdrawal of removable units {minimum number of cycles) 





Permanently 
installed units 


Non-permanently 
installed units 


Plug-in type 


50 


500 


Type with removable 
terminal blocks 


20 


500 



4.11 Battery requirements 

4.11.1 General 

Battery cases or compartments shall be designed to protect against accumulation of 



4.11.2 Non-rechargeable batteries 

1) Non-rechargeable batteries (e.g. lithium) if used shall be provided with suitable 
■Protection 'internal to the batter^ ceil or externa! comif^onents^ so as to minimize the 
risk of battery explosion. Parameters to be considered in the design should Include tem- 
perature, reverse current flow (charging), limited discharge, etc. to minimize the risk of 
battery charging. 

2) Means shall be provided to prevent inadvertent charging and to limit the discharge 
current of non-rechargeable batteries. 

4. 1 1 .3 Memory back-up 

Memory back-up requirements are expressed in 3,2.2. 

4. 1 2 Markings and identification 

Ay\2.A General marking requirements 

Each PC-unit shall be marked In a clear and legible manner as follows: 

1) manufacturer's name or trademark symbol; 

2) mode! number or name; 

3) software serial number and/or revision level (see item 6 of 6.2), where applicable; 



4) hardware serial number and/or revision level (see Item 6 of 6.2), and date code or 
equivalent; 

5) fuse replacement information, if applicable; 

6) power rating information in volts, amperes, and/or voltamperes, and frequency and 
polarity where connection to the mains power supply occurs; 

7) equipment class designation, If applicable. 



IS/IEC 1131-2(1992) 

I/O modules, shall be marked with their: 

1) rated voltage and current (as applicable); 

2) function Identifier. 

Live parts, protective earth terminals and functional earth terminals markings shall be as 
required in 4.12.2. 

4. 1 2.2 General identification requirements 

4. 12.2. 1 Functional identifications 

1) The function of each I/O module shall be unambiguously identifiable when it is 
placed in its service position and operating, by means of a convenient manufacturer's 
mark. 

2) All operator's switches, indicator lamps, and connectors shall be identified or have 
provisions for identification. 

4. 12.2.2 Module location and module identifications 

Space shall be provided for identification of eacn module and I/O channel on or near to 
the modules. 



4.12.2.3 External wiring terminals identification 

External wiring terminals shall be marked to indicate the proper connections for the power 
supply, load, control circuit, and the like, or a wiring diagram coded to the terminal mark- 
ing shall be provided. 



4.12.2.4 Uve parts 

A live part exceeding SELV limits and likely to be mistaken as dead-metal (non-energized 
metal) and exposed to personnel under normal installation or maintenance shall be 
marked with the following "Dangerous voltage" symbol (417-(EC-5036-a): 



h 



4.12.2.5 Protective earth terminals markings 

1) The protective earth terminals markings shall be durable and clearly identifiable. 

2) The identification shall be achieved by the notation PE according to 5.3 of lEC 445, 
or by a graphical symbol for use on equipment. 

66 



IS/IEC 1131-2(1992) 

3) The graphical symbol to be used is the symbol 4l7-IEC-5019-a shown below in 
compliance with lEC 417, which shall progressively supersede the previously recom- 
mended symbol (417-IEC-5017-a}. 




4. 12.2.6 Functional earth terminals markings 

Functional earth terminals (i.e. used for non-safety purposes such as noise immunity 
improvement) shall be marked with the following symbol 417-IEC-5018-a: 



^ 



5 information to be provided by the manufacturer 

5. 1 General 

The manufacturer shall provide users with information required for the application, design, 
installation, commission, operation and maintenance of the PC-system, in addition, the 
manufacturer may provide user training. 



In this subclause only the general concept of the written information to be provided is 
stated. The required informations to be given in each level of documentation as defined 
below, is listed in various subclauses of all parts of this standard. 

5.2 Index of information to be provided 

The following table 29 lists all cross references to other areas where manufacturer's 
information is required. 



67 



IS/IEC 1131-2(1992) 



Table 29 - \r\dex: Information to be provided 



Hart 



tiuociause 



uojuci 



Note 3 of 2.2.2.2 

2.1.1.3 

2.1.1.4 

2.1.1.5 

2,1.2.2 

2:1.3.1 

2.3 

2.3.6 

Note 3 of 3.2.1.1 

Note 5 of 3.2.1.1 

3.2.3 

Item 4 of 3.3 

Item 5 of 3.3 

Note 2 of 3.3 

3.3.1.4 

3.3.2.2 

3.3.2.2 

3.3.2.3 

3.3.3.3 

3.4.1.2 

3.4.2.2 

3.5.2 

3.6.3 

3.7.2 

3.8.2 

Note 1 of 3.9.1 

3.9.2 

3.10.3 

3.11.3 

Item 2 of 4.2 

Note 6 of table 2& (4.4.2) 

4.5.1 

4.5.2 

4.6.3 

4.12 

5.4 

5.5 

5.6 

Item 7 of 6.3.2.2 



Equipment ambient temperature limits 
Relative fiumidity 
'Pollution degree 
Corrosion protection 
Electrostatic discharge severity level 
Vibrations 

Special transport and storage conditions 
Transport and storage 
Sizing of a dedicated pow«er source 
Non-standard power supplies 
Power supply 
Additional external load 
A.C. inputs ted from several phases 
Non-standard digital l/Os 
Digital inputs 

Protected/non-protected outputs 
Short-circuit proof outputs 
A.C. digital outputs 

r^ rt riinital mitniite 

».. — . -..g.,_. ,._., 

Analog inputs 

Analog outputs 

Communication interfaces 

MPii, PC configuration 

Remote input/autput stations 

Peripherals 

Noise immunity 

Noise immunity 

Insulation properties 

Self-tests and diagnostics 

Warning labels/open equipment 

Terminal connections 

Enclosures (power dissipation) 

Enclosures (moving parts) 

Terminal connections 

Markings 

Compliance with this standard 

Reliability 

Safety 

Coverage factors 

Under consideration 

Under consideratiorr 

Under consideration 



IS/tEC 1131-2(1992) 

5.3 Type and contents of written documentation 
Three levels of documentation are defined: 

- catalogues and datasheets; 

- user's manuals; 

- technical documentation. 

5.3.1 Cataiogues and datasheets 

These documents shall contain the description and the specifications of the PC-system 
and its associated peripherals and other relevant information to aid in understanding the 
application and use of these products Including functional characteristics, equipment 
configuration rules, normal service conditions, physical dimensions and weights, and list 
compliances with standards and certifications. Moreover, these documents shall clearly 
specify the limits of the contract and of the guarantee of the manufacturer. 

5.3.2 User's manuals 

These documents shall include the necessary information for the proper installation, 
wiring, troubleshooting, user programming and commissioning of the PC-system. They 
Shalt include as a minimum: 

1) All information which is required throughout all parts of this standard (see table 29 
in 5.2). 

2) All information contained in catalogues and data sheets as required in 5.2. 

3) Installation and commissioning instructions. 

4) Programming and troubleshooting instructions. 

5) Maintenance and service requirements. 

6) Accessory and spare parts lists (e.g. fuses). 

5.3.3 Technical documentation 

The manufacturer optionally may provide a set of documents which contain more informa- 
tion than those given in the users manual such as: schematic diagrams, internal or 
external data protocols, bus assignments, physical dimension requirements, energy 
available, firmware, Internal test programs or repair procedures, etc. 



5.4 Information on compliance with this standard 

Compliance with parts 1 and 2 of this standard cannot be claimed unless all tests and 
verifications required in this part are complied with. See 6.2 for details. 

5.5 information on reliability 

It the manufacturer provides values of the mean time between failures (MTBF) of any 
subassembly or module, and of the type-test configuration(s) (basic PC-system(s)) under 
normal service conditions the manufacturer shall also explain the method used to 
determine it. 



69 



IS/IEC 1131-2(1992) 

5.6 Information on safety 

The manufacturer's data shall Include the following information as a minimum: 

1) Protective earthing requirements and recommendations concerning personnel 
safety circuits. 

2) Suggested requirements to the user for the maintenance of protective devices, such 
as protective earthing circuits, overcurrent protective devices, and batteries utilized for 
memory back-up, etc. 

3) If the PC-system is provided as "open equipment", the type of enclosure required to 
provide the required level of safety and environmental protection and guidelines for 
mounting, spacing, and/or internal barriers or shields if needed for safety. 



4) Precautionary instructions, if removal of any module while the equipment is in 
operation can affect safety related to electrical shock, fire hazard and electrical 
damage. 



6 Tests and verifications 

6.1 General 

The object of this clause is to define how to verify compliance of the programmable control- 
ler and the associated peripherals with the requirements set forth in parts 1 and 2 of this 
standard. This compliance verification includes: 

- verification by type tests given in 6.3; 

- verification by suitable examination, visual inspection or/and measurement. 

These tests are qualification tests, and not tests related to the ways PCs are applied: 
according to the scope of this standard, the above compliance verification may not cover 
the verification of the ability of the PC-system to satisfy the intended automated system 
requirements; where needed, special tests not covered by this standard shall be agreed by 
the manufacturer afid the user. 



In additlon^, routine tests are specified in 6.4. 

6.2 Compliance with this standard 

1) Compliance with parts 1 and 2 of this standard cannot be claimed unless all tests 
and verifications required in this part are complied with. Moreover, the manufacturer's 
obligations expressed in this part are not waived If no type test is required, or if the test 
conditions are restricted for practical reasons*. 

2) Compliance with constructional requirements and information to be provided by the 
manufacturer shall be verified by suitable examination, visual inspection, and/or 
measurement. 



On the other hand, user's obligations are considered in several subclauses of this part: t.l. 2, 3.2, item 2 
0(4.2,5.6. etc. and in lEC 1131-4. 

70 



IS/lEC 1131-2(1992) 

3) All Characteristics not tested according to this clause 6 shall be verifiable under a 
procedure to be agreed to by the manufacturer and the user. 

4) The manufacturer shall be able to give enough information on all requirements on 
this part when claiming compliance for his-implementation. 

5) It is the manufacturer's responsibility to ensure that delivered programmable control- 
lers equipment and associated peripherals are similar to the sample(s) which have 
been type-tested according to this standard and therefore that they comply with all 
requirements of this standard. 

6) Significant modifications shall oe indicated through the use of suitable revision level 
indexes, markings (see 4.12.1} and shall comply with this standard. 

NOTE - A new type test may be required to confirm contpliance. 

7) Where the manufacturer is allowed to select among several options he shall clearly 
specify in tiis catalogues and/or datasheets those to which any portion of the PC- 
system equipment complies. This applies to severity classes of voltage drops (i.e. PS1 
or PS2), relative humidity (i.e. RH-1 or RH-2), electrostatic discharges (i.e. ESD-3 or 
ESD-4), types of digital inputs (type I or type II). 

6.3 Type tests 

6.3.1 Equipment to be tested 

Basic PC-system(s) shall consist of: 

- the main processing unit (MRU); 

- remote input/output station(s) (RtOSs), i1 applicable; 

- and appropriate peripherals that can be connected and which are intended for use 
under the normal service conditions. 

If the PC-system is of modular structure: 

- the MPU and each RIOS of the basic PC-system(s) shall include at least one inter- 
face module of each type listed below it such a module Is supplied or recommended: 

• digital d.c. input module, digital d.c. output module, 

• digital a.c. input module, digital a.c. output module, 

• analog input module, analog output module, 

• communication interlace module, 

- appropriate catalogued options such as power supply units, application 
memory(ies). processing unit(s) etc. shall be used to build the basic PC-system(s). 

Peripherals shall be connected to their interface with the rest of the basic PC-system 
using the catalogued means or according to manufacturer's specifications. 

Unless otheoA/ise specified in this standard, the manufacturer may elect either that each 
type test be performed on a new basic PC-system or that several type tests be performed 
on the same basic PC-system. In any case each type test need not be performed more 
than once for a particular type of equipment. 



71 



IS/IEC 1131-2 (1992) 

For a family of very similar modules (i.e. modules using the same schematic and basic 
manufacturing and differing mainly by impedance adaptation), and for type tests which 
shall be obviously not dependent on the differences between the modules, the manu- 
facturer may elect to include in the basic PC-system only one arbitrarily chosen member of 
this family. 

Test configurations more simple than the basic PC-system may be used to verify 
unit/module and overall PC-system compliance when new units or modules are introduced 
to the marketplace after a modular programmable controller has been successfully tested 
according to this standard, provided that these test configurations and the appropriate test 
programs provided by the manufacturer allow proper verification as If they had been tested 
within the originally tested basic PC-system. 



See figure 1, page 47. 

6.3.2 Verification procedure 

6.3.2.1 General 

1) Type tests shall be conducted on the basic PC-system(s) defined In 6.3.1, unless 
otherwise specified. 

2) For each test, the manufacturer shall: 

- specify how this configuration shall be installed and externally connected; 

- provide the suitable test programs which sliall be run during the test; 

- provide the proper operation verification procedure including the way to measure 
accuracy and temporary deviations of analog l/Os. 

3) The appropriate test programs and proper functioning verification procedures 
provided by the manufacturer shall satisfy the requirements given in 6.3.2.2. 

4) The adequacy of the test programs and proper functioning verification procedures 
shall be verified by the measurement of the coverage factors for modules, units, 
external I/O wiring and removable connectors as required In Item 7 of 6.3.2.2. 

6.3.2.2 Requirements for test programs and proper functioning verification 
procedures (PFVPs) to be provided by the manufacturer 

1) During the type tests, there shall be no: 

- destruction of hardware; 

- modification of the operating system and test programs and/or alteration of their 
execution; 

- unintended modification of system and application data stored or exchanged; 

- erratic or unintended behaviour of the basic PC-system; 

- deviation of the analog 1/Os out of the limits specified in item 5 of 3.4.1.2.2 and 
Item 4 of 3.4.2.2.2. 



72 



IS/lEC 1131-2(1992) 

2) All relevant functions and parts of the basic PC-system (i.e. units, and modules) 
shall be functioning in such a way that the information pathis to/from these functions 
and parts are exercised. 

3) All the 1/0 and communication channels of the basic PC-system shall be exercised. 

4) All external and internal product status information reporting means such as 
displays, lamps, alarm signals, self-test results registers shall be exercised. The test 
procedures shall include conditions to verify the related activities. 

5) All various PC-system operation modes significant for the user's implementation 
such as start-up and shut-down, cold/warm/hot restart, "normal run", "normal stop", 
"program/monitor with PADTs", etc. as applicable shall be verified for performance and 
behaviour. 



6) Initialization and reset conditions of all system components shall be checked for 
controlled start-up and shut-down. The various modes such as "run", "program", 
"monitor", shall be verified for performance and betraviour. 

7) Coverage factors for modules, units, external I/O wiring and removable connectors 
of each test program shall be 100 %. This applies to fuses, batteries, etc. Optionally, 
the manufacturer should provide in his documentation satisfactorily information on the 
coverage factors of both the built-in self-tests and test programs for functions internal 
to modules/units. (Such factors cannot be equal to 100 %.) 



8) Any special feature/performance not covered in this standard but necessary to the 
proper operation of the basic PC-system shall be exercised and tested. 

NOTE - Depending on the interpretation of basic PC-system as defined in 6.3.1. the requirement of 
item 3 above may involve large amounts of equipment and highly complex procedures. Therefore, clarifi- 
cation of this requirement is under consideration. 

6.3.3 General conditions for tests 

1) The tests shall be carried out in accordance with the appropriate test procedure, 

2) The tests shall be carried out under the general test conditions given *m table 30 
below, unless othenwise specified. 

3) Unless otherwise specified, no sequence is imposed for type tests. 

4) Unless otherwise specified, the conditions given in table 30 shall apply. 

Table 30 - General conditions for tests 





Test conditions 


Mains power supply 


Rated voltage and frequency 


Temperature 


15 "0 to 35 "0 


Relative humidity 


45% to 75% 


Barometric pressure 


860 kPa to 1 060 kPa (650 mm Hg to 800 mm Hg) 


Output loads 


Outputs loaded to rated load 


Pollution 


Pollution degree 1 



73 



tS/lEC 1131-2(1992) 

6.3.4 Climatic tests 

6.3.4.1 General conditions 

1) Tests are p^ormed on unpackaged equipment. 

2) Temperature sensitive components tiiat are normally serviced and removed by the 
user may be removed, if so requested by the manufacturer. 

6.3.4.2 Dry heat and cold withstand tests 

Table 31 - Dry heat and cold withstand tests 



Dry heat 



Cold 



Reference test 



lEC 68-2-2, test Bb 



lEC 68-2-1, test Ab 



Preconditioning 
Initial measurement 
Conditioning 



According to manufacturer's specifications 
According to PFVP {6.3.2.2) 
Power supply unconnected 



Temperature 

Duration of exposure 

Measuring and/or loading 
during conditioning: 

Recovery 

• procedure 

• time 

• climatic conditions 

• special caution 

• power supply 
Final measurements 



+70 °C ± 2 "C 
96 h ± 1 h 



-25 °C ± 3 "C 
96 h ± 1 h 



None 



lEC 68-2-2, test Bb ) lEC 68-2-1 . test Ab 

1 h minimum 

See 6.3.3 

1 no condensation (note 1) 
Power supply unconnected 
According to PFVP (S.3.2.2) 



NOTE - All external and internal condensation shall be removed by air flow prior to connecting 
again the basic PC-system to a power supply. 



74 



IS/lEC 1131-2(1992) 



6.3.4.3 Variation of temperature 

Table 32 - Change of temperature, withstand and immunity tests 



Withstand test (note 1) 



Immunity test (note 2) 



Reference test 



lEC 68-2-14, test Na 



lEC 68-2-14. testNb 



Preconditioning 
Initial measurements 
Conditioning 



According to manufacturer's specifications 
According to PFVP (6.3.2.2) 
Power supply unconnected 



Low temperature 

High temperature 

• open equipment 

• enclosed equipment 
Exposure time at each temperature 
Transport time 

Temperature variation speed 

Number of cycles 

Measurement and/or loading 
during conditioning 

Recovery 

• procedure 

• time 

• climatic conditions 

• power supply 
Final measurements 



-25 "C ± 3 °C 

+70 °C ± 2 "C 
+70 °C ± 2 "C 
3 h ± 30 min 
Less than 3 min 
Not applicable 
2 

None 

IEC68-2-14. test Na 

Less than 2 h 

See 6.3.3 (note 5} 

Power supply unconnected 

According to PFVP 
(6.3.2.2) 



+5 "C ± 2 "C (note 3) 

+55 °C ± 2 "C (note 3) 

+40 'C t,2 "C (note 3) 

3 h A3p min 

Not applicable 

3 °C/min ± 0,6 "C/min 

5 

Note 4 

Not applicable 
Not applicable 
Not applicable 



NOTES 

1 PFVP according to 6.3 performed after recovery. 

2 PFVP according to 6.3 performed during test. 

3 The time for stabilization of temperature depends on the load and the test program: this time is 
included in the exposure time. 

4 Multichannel output modules shall be derated as specified by the manufacturer. 

5 All external and internal condensation shall be removed by air flow prior to connecting again 
the basic PC-system to a power supply. 



75 



JS/IEC 1131-2(1992) 

6.3.4.4 Cyclic damp heat withstand test 

Table 33 - Cyclic (12 + 12) damp heat withstand test 



Reference test 


lEC- 68-2-30. test Db 


Preconditioning 


According to manufacturer's specifications 


Initial measurements 


According to PFVP (6.3.2.2) 


Conditioning 


None 


Details of mounting/support 


None 


Variant 


2 


Special precautions 


Power supply disconnected 

■ 


Temperature 


+55 "C 


Number of cycles 


2 


Measurement and/or loading 
during conditioning 


None 


Recovery 




• procedure 




• time 




• climatic conditions 


Under controlled conditions prescribed in lEC 68-2-30 


• power supply 


Power supply disconnected (note) 


Final measurements 


Dielectric test and insulation test in addition 
to PFVP (6.3.2.2) 



NOTE - Ail external and internal condensation shall be removed by air flow prior to connecting 
again the basic PC-system to a power supply. 



76 



IS/lEC 1131-2(1992) 



6.3.5 Mechanical tests 

6.3.5.1 Vibrations (type test associated with normal service conditions) 

Table 34 - Immunity vibration test 



Reference test 


tEC 68-2-6, test Fc 


Requirement reference 


Subclause 2.1.3.1 


Preconditioning 
Initial measurements 
Details of mounting/support 


According to manufacturer's specifications 

According to PFVP (6.3.2.2) 

According to manufacturer's specifications 
for portable and fiand-held portable equipment 


Motion 

Vibration amplitude/acceleration 

10 Hz < f < 57 Hz 

57Hz < f < 150 Hz 
Vibration type 
Vibration duration 

Measurement and verification during loading 
Verification after tests 


Sinusoidal 

0,075 mm amplitude 

1,0 g 

Sweeping, at a rate of 1 octave/min (± 10 %) 

10 sweep cycles per axis on each of 
tfiree mutually perpendicular axes 

According to PFVP (6.3.2.2) 

According to PFVP (6.3.2.2) 



6.3.5.2 Shocks (type test associated with normal service conditions) 

Table 35 - Immunity shock test 



Reference test 


lEC 68-2-27, test Ea 


Reference test 


Subclause 2.1.3.2 


Preconditioning 
Initial measurements 
Details of mounting/support 


According to manufacturer's specifications 

According to PFVP (6.3.2.2) 

According to manufacturer's specifications 
for portable ^nd hand-field portable equipment 


Type of sfiock 
ShocK severity 
Application 

Measurement and verification during loading 
Verification after tests 


Half sine 

15 g peak, 1 1 ms duration 

Two shocks per axis, on three 
mutually perpendicular axes 

Accordinjg to PFVP (6.3.2.2) 

According to PFVP (6.3.2.2) 



77 



IS/I EC 1131-2(1992) 



6.3.5.3 Free falls (type test associated with normal service conditions) 

Table 36 - Free falls immunity/withstand tests {portable and 
hand-held portable equipment) 



Reference tests 

• Random and flat drops 

• Supported drops 


lEC 68-2-32. procedure 1 
lEC 68-2-31, subclause 3.2.1 


Requirement reference 


Subclause 2.1.3.3 


Preconditioning 
Initial measureoients 
Details of mounting/support 


According to manufacturer's specifications 

According to PFVP (6.3.2.2) 

Equipment equipped with catalogued cable{s) 


Measurement and verification during loading 
Verification after tfie tests 


According to PFVP (6.3.2.2) 
According to PFVP (6.3.2.2) 



6.3.5.4 Free falls (type test associated with transport and storage conditions) 

Table 37 - Free falls withstand test (units within manufacturer's original packaging) 



Reference test 


lEC 68-2-32, procedure 1 


Requirement reference 


Subclause 2.3.4 


Selection of samples 

Initial measurements 
Details of mounting/support 


Each type of manufacturer's original packaging 
with the heaviest unit using it 

According to PFVP (6.3.2.2) 

Equipment equipped with catalogued cable(s) 


Measurement and verification during loading 
Verification after tfie test 


None 
According to PFVP (6.3.2.2) 



78 



IS/I EC 1131-2(1992) 



6.3.5.5 Safety related tests 

6.3.5.5.1 Impact withstand test (type test associated with transport 
and storage conditions) 



■r^i_i _ no 



L»^^ *. «i« 



I autts oo — iiiifjciui wiiiibieiiiu i»:>i 



Reference test 


lEC 950 


Requirement reference 


Subclause 4.5.3.6 


Selection of sample{s) 

Exceptions 

Initial measurements 
Details of mounting/support 


Enclosed equipment with voltage greater than SELV and 
equipment containing moving parts 

Test perfornred neither on hand-held portable equipment 
nor on displays nor lamps 

According to PFVP (6.3.2.2) 


Description of the test 
Number of trials 
Verification after tfie test 


See figure 6 below 

One per surface 

Perform the accessibility test (6.3.5.5.2) 
Perform the dielectric test (6.3.6.1.1) 


* Tfie unit may be non-functioning after the test. 



Impact test procedure: 



The impact is imparted to the sample by a solid, smooth steel sphere approximately 
50 mm in diameter and with a mass of 500 a ± 25 a (see fiaure 6 below) 



- Top surfaces: 



The sphere is to fall freely from rest through a vertical distance 
of 1 300 mm to the rest of the top surfaces. 



Vertical surfaces: The sphere is suspended by a cord and swings as a pendulum 
dropping through a vertical distance H of 1 300 mm to the 
sphere impact position. 



79 



IS/IEC 1131-2(1992) 



Sphere start 
position 







Sphere impact 
position 



o 

a 

a 

•3 
m 

CO 

& 

■g 
a 
(D 

'2 
i? 
0: 



Test sample 



Rr^ktSuppOrl^l^ SUtfAtUi 



Notfr; 

H = 1 300 mm 

For the ball pendulum impact 

test, the sphere is to contact 

the test sample when the 

cord is in the vertical 

position as shown 



Sphere start 
position 




Test sample 



Sphere impact 
N^ ^position 



ntglci &it>porfln$ jlt^fac^ 



JBC 9S9/92 



Figure 6 - Impact withstand test procedure 
6.3.5.5.2 Accessibility tests 

Table 39 - Accessibility tests* 



Reference tests 

• Class I equipment 

• Class 11 equipment 



lEC 529 

lEC 950. subclause 2.1, 
t<«st pin of figure 20 



Requirement references 



Subclauses 4.2, 4.5.2 and 4.5.3 



Selection of sample(s) 

Number of samples 

Preconditioning 

DetaiiS of mounting/support 

Drain/ventilation holes 

Moving parts test 

Electrical shock test 



Glass I and Class It enclosed equipment and 
enclosed equipment containing moving parts 

One equipment of each type 

Clean and new 

According, to manufacturer's specifications 

Configuration used in operating conditions 

Equipment energized and operating 

Equipment de-energized 



Test description 



The finger (IP2X} and, where applicable, the test pin 

shall not make contact with any live part 

(except for SELV circuits) or any moving part 

(except smooth rotating shafts) 



* For open equipment, no test is^ required, and the user is responsible for the safety of the equip- 
ment. 



80 



IS/IEC 1131-2(1992) 

6.3.5.5.3 Verification of clearance distances at field wiring terminals 

Table 40 - Verification of clearance distances at field wiring terminals 



Reference test 


Physical measurement 


Requirements references 


Subclauses 4.3 and 4.5 



6.3.5.5.4 Verification of internal/external wiring characteristics 

Integrity of internal/external wiring 

This integrity stiall be initially tested and then verified during the vibration tests specified 
in 6.3.5.1, and after the vibration, shocl< and free fall tests specified in 6.3.5,1, 6.3.5.2 and 
6.3.5.3. 

Wire and cable flexing withstand test 

- Requirement reference: subclause 4.9.2 

The flexing test applies to wiring subject to flexing under normal service conditions and 
maintenance, and where conductors are solid or insulation is less than 0,8 mm thick. 

- Test procedure: 

The flexing test consists of flexing the wire/cable assembly between the two extreme 
points of travel for the cable. 

Number of flexing cycles: 

• 500 if flexing under normal service conditions; 

• 25 if flexing only during maintenance operations; 

- Pass/fail criteria: 

The wiring shall be considered acceptable if after this test: 

• the PFVP (6.3.2.2) is performed successfully; 

• the insulation passes Ihe application of the dielectric test (6.3.6.1.1 and the fol- 
lowing insulation breakdown test method); 

- Insulation breakdown test method: 

The wiring being tested is removed from the equipment and the portion of the cable 
having been flexed is wrapped with a conducted foil. The applicable test voltage as 
given in table 17 in 3.10.2 is then applied between each conductor in turn and the 
common connection of all other conductors and this conducting foil. 

Mechanical properties of terminals 

NOTE - The applicability of the requirements of lEC 947-1 to this subclause is under consideration. 



!1 



IS/IEC 1131-2(1992) 

Verification of the protection against the effect of improper connections 

- Requirement references: 

Item 2 of 3.8.1, 4.9, item 2 of 4.12.2.1, 4.12.2.3 to 4.12.2.6. 

- Verifications: 

Connectors shall have either mechanical key or proper warning to prevent improper 
connections. User's manuals shall indicate correct connections to be made and include 
appropriate warnings as applicable. 

Routing of wirings 

- Requirement reference: subclause 4.9.4. 

6.3.5.5.5 Flammability of insulating materials 

- Requirement reference: subclause 4.4. 

Applicable tests shall be performed for each material for which the manufacturer does 
not provide an acceptable compliance certificate. 

6.3.5.5.6 Temperature rise test 

Table 41 - Temperature-rise test 



Reference test 


Not applicable 


Requirement reference 


Subclause 4.4.2 


Preconditioning 
Initial measurements 
Details of mounting/support 
Loading 


According to manufacturer's specifications 

According to PFVP (6.3.2.2) 

According to manufacturer's specifications 

The basic PC-system shall be operated with all 

I/O modules at their rated *ON' operating conditions 

(too % duty cycle) 


Measurement and verification during loading 
Verification after the tests 


According to PFVP (6.3.2.2) 
According to PFVP (6.3.2.2) 



6.3.5.5.7 Protective coating test 

Requirement reference: subclause 4.3.3.1.2. 
NOTE - Alternative tests are under consideration. 

1) Testing shall be done on test-PWBs with parallel printed conductors with a length of 
at least 100 mm, whereby the creepage distances have to be in accordance with the 
actual application. For the test-PWB, the same coating material, the same PW6 
material, and the same manufacturing (processing) procedure shall be used as during 
the normal equipment manufacturing procedure. 



82 



IS/IEC 1131-2(1992) 

2) The test shall be done on three test PWBs. The sequence of tests shall be: 

a) ageing of samples. 

b) dielectric test. 

c) adherence test. 

3) Ageing of samples 

Reference test: lEC 68-2-3, test Ca 

- test time (warm damp, constant): 56 days 

- storage time and conditions: 28 days at 11 **C 

- pass/fail criteria: the dielectric test and the adherence 

test have to be passed thereafter 

4) Dielectric.test 

Procedure: 

Select the d.c. test technique and test voltage levels in accordance with the applicable 
dielectric withstand requirements of 3.10. Perform the test on three test PWBs; the test 
voltage shall be applied between: 

a) their parallel printed conductors; 

b) these printed conductors and a test electrode that is put on the PWB. 
Pass/fail criteria: 

There shall be no flashoveror breakdown of the insulation. 

5) Adherence test (cross-cut adherence test) 

Multi'blade tool: 

The cutting tool shall be as defined in figure 7. The distance between two blades shall 
depend on the thickness of the protective coating: 

thickness in \im: distance between blades (a/5) 

thickness < 60: 1 mm 

60 < thickness < 120: 2 mm 




The leading edges and all cutcing edges 
shall have the same diameter 




grinding turiace. 



X iiO.05 (if cutting edges are worn more 
0.1 mm. re^jrinding is necassar 



then 
necassary). 



cutting direction. 



lEC 9d0l92 

Dimensions in millimetres 



Figure 7 - Multiblade tool with six blades 

83 



IS/IEC 1131-2(1992) 

Handbrush: 

The handbrush shall have 110 to 150 bundles of polyamlde bristles; each bristle shall 
be 12 mm to 15 mm long and 0,4 mm to 0,5 mm thick. 

Procedure: 

The appropriate cutting tool shall be used to draw two perpendicular cuts down to the 
basic material so that a grid of 25 squares results. The cut shall be drawn smoothly 
(not jerkily) with a speed of 0,02 m/s to 0.05 m/s. 

A magnifying glass shall ber used to verify that the cuts have suitably reached the basic 
material. The handbrush shall be used to brush the grid five times forth and back in a 
diagonal direction under soft pressure. 

Pass/fail criteria: 

Total chipped area shall be smaller than 5 % of the grid area. No separation, fracturing, 
or delamination of the coating from the surface of the base material or conductor is 
allowed. 

6. 3 .5.6 Verification of terminal connection characteristics 

Verify that requirements of 4.6 are met. 

6-3.5.7 Plugging/unplugging of removable units 

Table 42 - Insertions/withdrawals of removable units 



Requirements references 


Subclause 3.8.1, item 1 of 3.9^1. 4^.9 and 4.10 


Description of the test for 
permanently installed units 

Description of the test for 

no n -permanently installed units 


SO (20) insertions/withdrawals are performed without power; 
then the equipment shall pass the PFVP (6.3.2.2) 

500 insertions/withdrawals are performed while 

the basic PC-system is performing functional test programs 

as required for PFVP (6.3.2.2) 

Insertions and withdrawals shall not affect 

the proper operation of the basic PC-system. 

Communication on the physical link during the test 

is not required. 



6.3.6 Electrical tests 

CAUTION: It may be necessary to Install an external Impedance (a filter) to protect the 
test equipment that is connected to the basic PC-system being tested. 



6.3 .6 . 1 » Safety related tests 
6.3.6.1 .1 Dielectric test 

Exceptions: 

These tests need not be done: 



84 



IS/IEC 1131-2(1992) 

- between isolated SELV circuits and accessible conductive parts (frames, 
enclosures, earth terminal, etc.) 

- on units (parts of the basic PC-system) which have been tested separately accord- 
ing to the relevant standards, provided: 

a) the values given in table 17 in 3.10.2 have been met, and 

b) their dielectric strength is not impaired by assembly. 

- between isolated circuits on printed wiring boards providing the specified 
clearances and creepage distances have been met. See 4.3. 

Test conditions: 

The tests are done on each unit and module connected In the test circuit as shown in 
figure 6. If required, tests can be done on individual modules with the remaining modules 
removed. All mechanical switches shall be in the "ON" closed position. 



Test technique: 

One may select any one of the following techniques: 

- Impulse test, according to lEC 60-1 and the following conditions: 
Pulse characteristics: 1 ,2/50 ps ± 20 % 
Source impedance: 500 ±10% 

Source energy: 0,5 J ± 20 % 

Length of connection: < 2 m 

Number of impulses: 3 positive and 3 negative 

Time between two impulses: > 5 s 

- a.c. r.m.s. voltage test 

Number of periods: >. 3 

Voltage signal: starting from V (zero crossing) 

Short-circuit current: < 5 mA 

- d.c. voltage test 

Pulse duration at d.c. value: 10ms± 20% 

Pulse rise/fall times: > 1 ,2 ps 

Number of pulses: 1 positive and 1 negative 

Time between pulses: < 5 s 

Short-circuit current: < 5 mA 

NOTES 

1 In generaJ. preference should be given to the impulse test; however, where filter capacitors are used 
(line to earth), the d.c. test is recommended. 

2 See annex D: correction factors for test voltages corresponding to barometric pressure or altitude. 

3 To recognize current practice, the manufacturer may elect alternatively to verify the dielectric strength 
by the application of 2 Lf + 1 000 V a.c, for a minimum duration of 1 min. 



85 



IS/IEC 1131-2(1992) 



Isolated o 
ctrcuit 










Isolated o 
circuit « 








Method a 

Test between each 

isolated CIRCUIT sequentially 

and the others together 



Isolated 
ctrcuit 



Isolated 
circuit 



Isolated 
circuit 



Isolated circuit o 
Under test > 



SELV circuit o 




AMP: Accessible Metal Parts 

Method b 

Test between each 

ACCESSIBLE 

CONDUCTIVE PARTS and 

each non-SELV CIRCUIT separately 




Method c 

Test between each 
SELV-CIRCUIT and 
non-SELV CIRCUITS 



lEC 961192 



Figure 8 - Dielectric test procedures 

Test method: 

Th(9 test voltage shall be applied as follows: 

a) Between isolated circuits other than SELV circuits 

The test voltage shall be applied between each isolated circuit and the remaining 
circuits connected together to the earth. The test voltage shall be that given in table 17 
in 3.10,2 corresponding to the highest rated voltage and class of the circuits. 

b) Between isolated circuits other than SELV circuits and accessible conductive parts 
(frame, enclosure, protective earth terminal, functional earth terminal, etc.) 

The voltage shall be applied between each isolated circuit sequentially and accessible 
conductive parts. The test voltage shall be that given in table 17 in 3.10.2 correspond- 
ing to the rated voltage and class of the circuit. 

c) Between isolated SELV circuits and other non-SELV circuits 



The test voltage shall be applied between each isolated SELV circuit and the remaining 
non-SELV circuits connected together to the earth. The test voltage shall be 1500 V 
a.c. r.m.s. or its equivalent peak value for the impulse and d.c. 

Pass/fail criteria: 

There shall be no unintentional (lashover or breakdown of the insulation during the test. 
Eventual operation of protecting devices provided on the units shall not be considered as 
a failure (an intentional flashover Is one which might be the result of the normal action of a 
surge suppression device incorporated in the equipment). 

86 



IS/lEC 1131-2(1992) 

6.3.6.1 .2 Protective earthing continuity test 

Requirement reference: item 6 of 4.7.2 

Test description: 

A constant current of 30 A tor at least 2 min stiall be injected between the earthing 
terminal or contact and each of the accessible metal parts intended to be earthed. 
The current shall be maintained or adjusted accordingly during the test to 30 A. Any 
convenient low voltage not exceeding 12 V can be used. The voltage drop shall be 
measured between the points of current flow, care being taken that the contact resistance 
between the tip of the measuring probe and the metal part underneath does not influence 
the test results. 

Pass/fail criteria: 

The resistance shall not exceed 0,1 a. 

6.3.6. 1 .3 Stored energy injury r/s/c test 

Requirement reference: subclause 4.5.3.3. 

Selection of samples: 

Portable peripherals connected to the mains power supply by use of a cordset (removable 

or fixed) shall comply with this test. 

Test description: 

- the test shall be applied to each individual pin of the plug and to the receptacle; 

- the cordset shall be disconnected from the mains power supply, the peripheral 
being in operation; 

- in a delay not exceeding 1 s from the instant of deconnection, and for each of the 
pins/receptacle, both the voltage and the short-circuit current between the pin or recep- 
tacle tested and the local protective earth shall be measured. 

Pass/fail criteria: 

For all tests (i.e. one test per pin or receptacle), the voltage shall not exceed 42,4 V peak 

or d.c, or 30 V r.m.s. and the discharge current shall not exceed 5 mA. 

6.3.6.2 Noise immunity tests 
6.3.6.2.1 Electrostatic discharge test 

The following test is considered to be a first step in the direction of commonly used tests 
for the qualitative evaluation of the performance of electronic equipment. 



87 



tS/lEC 1131-2(1992) 



Table 43 - Electrostatic discharge immunity test 



Reterence test 


lEC 801-2 


Requirement reference 


Subclause 3.9.1 


Preconditioning 
initial measurements 
Derails of mounting/support 
Selection of application points 

• Exception 


According to manufacturer's specifications 

According to PFVP (6.3.2.2) 

According to manufacturer's specifications 

All exposed conductive parts and insulating 

surfaces of the basic PC-system normally accessible 

to the operator (see 3.9.1) 

Signal lines; circuits or live parts becoming accessible 
only during maintenance operations 


Discharge characteristics 
• test peak voltage 
RH-1 /ESD-3 

RH-2 / ESD-4 

Time between two discharges 

Number of discharges on each 
selected point 

Measurement and verification during loading 

Pass/fail criteria 


8 kV 
15 kV 

> 1 s 

10 discharges after the equipment 
is discharged to earth 

According to PFVP (6.3.2.2) 

There shall be no deviation other than allowances 

for analog and fast responding l/Os. 

If the system deviates only once during the test, 

a second trial of 10 discharges shall be performed; 

if only one more unallowed deviation is observed, 

failure to the ESD test shall be declared 



6.3.6.2.2 Radiated electromagnetic field test 

Table 44 - Radiated eiectromagnetic field immunity test 



Reference test 


lEC 801-3 


Requirement reference 


Subclause 3.9.1 


Preconditioning 
Initial measurements 
Details of mounting/support 

Frequency range to be swept 

Sweep speed 

Test field strength 

Measurement and verification during loading 

Pass/fail criteria 


According to manufacturer's specifications 

According to PFVP (6.3.2.2) 

The basic PC-system is placed on a wooden table 
in a shielded room, in the far field 
generated by the radiated antenna. 

27 MHz to 500 MHz 

3 
1,5 X 10 decade/s 

10 V/m 

According to PFVP (6.3.2.2) 

There shall be no deviation other than manufacturer 
specified allowances for analog l/Os. 



88 



IS/I EC 1131-2(1992) 



6.3.6.2.3 Fast transient burst test 



Table 45 - Fast transient burst immunity test* 



Reference lest 


lEC 801-4 


->Ret)uirement reference 


Subclause 3.9.1 


Preconditioning 
Initial measurements 
Details of mounting/support 

Severity level at rated voltage 

• A: (s wower supplies) 

• B: (digital l/Os. U^ 2 24 V) 

• C: (digital l/Os. U^ < 24 V. 

analog l/Os, communication l/Os) 

Duration 
. Application points/metfiods 

• A 

• BandC 


According to manufacturer's specifications 

According to PFVP (6.3.2.2) 

The test equipment configuration shall be such as 

to eliminate the radiated EMI received on 

I/O wiring by the specified capacitive coupling 

According to requirement in 3.9.1 
2 kV, repetition frequency of spikes; 2.5 kHz t 20 % 
1 kV, repetition frequency of spikes: 5 kHz ± 20 % 
250 V. repetition frequency of spikes: 5 kHz ± 20 % 

10 s minimum 

Positive and negative common mode 

Direct coupling by wired capacitance method 

Capacitive clamp method 


Measurement and verification during loading 
Pass/fait criteria 


According to PFVP (6.3.2.2) 


* The repeatability of tfiis test is closely related to the number and relative position of wires within 
the capacitive coupling. 



. 89 



IS/IEC 1131-2(1992) 



6.3.6.2.4 Damped oscillatory wave test 






Reference test 



lEC 255-4 



Requirement reference 



Subclause 3.9.1 



Precondition tng 
Initial measurements 
Details of mounting/support 



According to manufacturer's specifications 

According to PFVP (6.3,2.2) 
According to manufacturer's specifications 



Test description 

• waveform 

• frequency 

• source impedance 

• repetition rate 

• test duration 

• lengtfi of connection 

• severity level at rated voltage 

A; (all power supplies) 

B; (digital l/Os, U^ i 24 V) 

C: (digital l/Os. U^ < 24 V. 

analog l/Os, communication 1/0$) 

• Application points/method 

A 

B 
Measurement and verification during loading 
Pass/fail criteria 



See figure 9 below 

Damped oscillating wave the envelope of which reaches 

50 % of the initial peak value after 3 to 6 cycles 

(verify the sinusoidal shape of the wave) 

1 MHz 

200 ft ± 10 % 

400 per s 

2 s minimum 

2 m maximum 

According to requirement in 3.9.1 

1 kV 

1 kV 

No test 

Series mode 

Wiring terminals 

Wiring terminals 
According to PFVP (6.3.2.2) 
There shall be no deviation 



90 



Power supply 
source 



IS/IEC 1131-2(1992) 

Equipment under test 




Interference source 

Figure 9 - Connection diagram tor damped oscillatory wave test series mode 
(normal mode) 

6.3,7 Verification of a.c. and d.c. power supply characteristics 

Perform the proper functional verification procedure of 6.3.2.2 during tests under 6.3.7,1., 
6.3.7.2 and 6.3.7.3. 

6.3 ,7. 1 Incoming power supply voltage and frequency variation tests 
6.3.7.1 .1 Voltage and frequency range test 

TaWe 47 - Voltage and frequency range immunity test (note 1) 



lEC 962192 



Reference test 


None 


Requirement reference 


Subclause 3.2.1.1 


Preconditioning 


According to manufacturer's specifications 


Initial measurements 


According to PFVP (6.3.2.2) 


Description of tests 


Test A Test B 


• a.c. voltage {k % U^) (note 2) 


0.85 1.10 


• a.c. frequency {k x F^) (note 2) 


0.95 1,05 


• d.c. voltage (k x U^) (note 2) 


0,85 1.20 


• ripple continuous {kx LL) (note 2) 


0,05 0,05 


• test duration 


30 min 30 min 


Measurement and verification during loading 


According to Pf=VP (6.3.2.2) 


Verification after tests 


According to PFVP (6.3.2.2) 







NOTES 

1 If ttiere are separate mains supplies to the PC-system tfie tests may be done on each supply 
separately. 

2 See precise definitions in 3.2.1 .1 . 

91 



IS/IEC 1131-2(1992) 

6.3.7.1 .2 Third harmonic immunity test 

Table 48 - Third harmonic immunity test* 



Reference test 


None 


Requirement reference 


Subclause 3.2.1.1 


Preconditioning 
Initial measurements 


According to manufacturer's specifications 
According to PFVP (6.3.2.2) 


Description of tests 

Test duration for each phase 

Measurement and verification during loading 

Verification after tests 


A third harmonic voltage (150 Hz or 180 Hz) 

adjusted to 10 % of the mains rated voltage 

is added to the a.c. mains power supply 

with 0° and 180° (see figure 10) 

5 min 

According to PFVP (6.3.2.2) 

According to PFVP (6.3.2.2) 


* If there are separate mains supplies to the PC-system the tests may be done on each supply 
separately. 




Third harmonic 
generator 



UtjuuuuummmjiM 



Power 

^X^ ) supply 

source 




lEC 963192 



Figure 10 - Third harmonic immunity test 



92 



IS/lEC 1131-2(1992) 



6.3.7.2 External energy supply interruption tests 
6,3.7.2.1 Momentary interruption immunity test 

Table 49 - Momentary external energy supply interruption immunity test 



Reference test 


None 


Requirement reference 


Subclause 3.2.1.2 


Preconditioning 
initial measurements 
Supply voltage and frequency 


According to manufacturer's specifications 

According to PFVP (6.3.2.2) 

Rated values 


Test description 

A.C. supply interruption 

• duration, base 

• number of trials 

• time interval between trials 
D.C. swpply interruption 

• duration 

• number of trials 

• time interval between trials 
Measurement and verification during loading 

Verification after the tests 


0,5 period, starting at zero-crossing (notes 1 and 2) 

20 

1 s £ time interval £ 10 s 

PSI: 1 ms; PS2: 10 ms; (note 2) 

20 

1 s i time interval < 10 s 

According to PFVP (6.3.2.2) 
Normal operation shall be maintained (note 3) 

According to PFVP (6.3.2.2) 


NOTES 

1 Optionally, tfie manufacturer may elect to interrupt the supply at a random phase angle. 

2 The manufacturer may state longer interruptions. 

3 Fast responding inputs energized by the same power supply ~tnay be affected temporarily 
during the disturbance but shall resume normal operation after the disturbance. 



6.3.7.2.2 Shut-down test (sudden supply interruption) 

Requirement reference: Item 2 of 3.2,1.2 

Test description: 

During shut-down due to the supply interruption the system behaviour shall be observed. 

The test is repeated twice. 

Pass/fail criteria: 

The requirement given above shall be met. In addition, from the start of interruption to 
Shut-down, there shall be no change not caused by the normal test program and no erratic 
or unintended condition of any kind. 



93 



IS/lEC 1131-2(1992) 

6.3,7.2.3 Start-up test (voltage applied normally) 

When the external supply is applied for a time specified by the manufacturer, the 
PC-system shall start again according to the specifications of the manufacturer (automatic 
or manual restart, initialization sequence, etc.). During the start-up there shall be no 
erratic or unintended condition. 

6.3.7.3 External energy supply variation tests (immunity tests) 
6.3.7.3.1 General 

Reference requirements: subclause 3.2.1.2. 

At voltages below the minimum normal service conditions limits and/or frequencies beyond 

the normal conditions limits, the PC-system shall "either maintain normal operation or go 

to a predefined state and have^ a clearly specified behaviour until normal operation is 

resumed". 

Pass/fail criteria: 

During the tests, the PFVP (6.3.2.2.) shall insure that the behaviour of the basic 
PC-system Is as specified by the manufacturer and that there is no change not caused by 
the PFVP test program and no erratic or unintended conditions of any kind. 



6.3.7.3.2 Gradual shut-down/start-up test 

Table 50 - Gradual shut-down/start-up test 



Reference test 



None 



Requirements references 



Subclause 3.2.1.2, items 6 and 7 of 3.2.3, 
item 17 of 3.3.2.3 



Preconditioning 



The befiaviour of ttie basic PC-system sfiati be according 

to PFVP (6.3.2.2) at minimum operational voltage 

and frequency (test A of 6.3.7.1.1} 

and at maximum operational voltage and 

frequency (test B of 6.3.7.1 .1 ) 



Te$t description 

• initial/final conditions 

• lowest voltage (V) 

• speed of voltage decrease/increase (V/s) 

• waiting time at lowest voltage (s) 

• number of trials 

• time interval between trials 
Measurement and verification during loading 

• voltage shut-down limit (SDL) 



• average SDL {SDL,^ ) 
Pa$s/fail criteria 



See figure 11. test A 

Power supply at rated values (U^. F^> 

(zero) 

Ug / 60 ± 10 % 

10 SI 20% 

3 

1 s < time interval s 10 s 

According to PFVP (6.3.2.2) 

The voltage at which the basic PC-system starts 
the manufacturer's specified shut-down sequence 

or initiates a behaviour not in accordance with 
the PFVP during the decreasing voltage sequence. 

The average of three measured SDL 



According to 6.3.7.3.1 



94 



IS/IEC 1131-2(1992) 



6.3.7.3.3 Gradual supply voltage variation tests 

Table 51 - Gradual supply voltage variation tests 



Reference test 


None 


Requirements references 


Subclause 3.2.1.2. items 6 and 7 of 3.2.3, 
item 17 of 3.3.2.3 


Preconditioning 


The behaviour of the basic PC-system shall be 
according to PFVP (6.3.2.2) at mintmum operational 

voltage and frequency (test A of 6.3.7.1.1) 

and at maximum operational voltage and frequency 

(teste of 6.3.7.1.1) 


Description of tests 

• initial/final conditions 

• lowest voltage (V) 

• speed of voltage decrease/increase (V/$) 

• waiting time at lowest voltage (s) 
-» number of trials 

• time interval between trials 
Measurement and verification during loading 
Pass/fail criteria 


Test B 
(fast variations) 
(see figure 11) 


Teste 

(stow variations) 

(see figure 11) 


Power supply at rated values {U , F ) 

(zero) 0,9 SOL^^y ± 10 % (note) 

a^/5±10% a/ 60 ±10% 

(zero) (zero) 

3 3 

1 s < time interval £ 5 s 

According to PFVP (6.3.2.2) 

According to 6.3.7.3.1 


NOTE - SOL,^ is a result of gradual shut-down test (see 6.3.7.3.2). 



95 



IS/lEC 1131-2(1992) 



60 s± 10% 




Slope (V/s): yfi±io% 
' 60 



PC-SYSTEM starts 
shut-down procedure 
or initiates abnormal 
procedure 



60s ±10% 



{*) According to manufacturer's 
speaficaiion or 10 s t 20 % 



Test A : Gradual shut-down / start-up test 

Ss Ss 




t(s) 



max. : 5 s min. : 1 s 




Test B : Fast supply 

voltage variations 



Test C : Slow supply voltage variations 



Figure 11 - External energy supply variation tests 

6.3.7.4 Improper power supply connection tests 
Requirement reference: item 5 of 3.2.3. 

6.3.7.4.1 Reversal of d.c. power supply polarity test (withstand test) 

The rated voltage of reverse polarity shall be applied for 10 s. The results shall comply 
with the conditions stated by the manufacturer (such as fuse blowing). 

After the test the basic PC-system shall pass the proper verification procedure (see 
6.3.2.2). Protective devices such as fuses may be reset prior to verification. 

6.3.7.4.2 Improper voltage level and/or frequency test 

For voltage level above the maximum normal service conditions limit U^ max. or/and 
frequencies beyond the normal service conditions limits F^ max. and F^ min., the test shall 
be agreed between the user and the manufacturer. 



96 



IS/lEC 1131-2(1992) 



6.3.7.5 Verification of memory back-up characteristics 
6.3.7.5.1 Back-up duration withstand test 

Table 52 - Back-up duration withstand test 



Reference test 


None 


Requirements references 


Subclause 3.2.1.2, items 6 and 7 of 3.2.3, 
item 17 of 3.3.2.3 


Preconditioning 
Duration of preparation 

Test to be performed 


According to PFVP (6.3.2.2) 

According to manufacturers specifications 
(energy source may require time to be fully cfiarged) 

Eitfier test A or test B defined below 


Description of tests 

• initial conditions 

• temperature (°C) 

• duration (h) 
Verification after tfie tests 


Test A 


Test B 


Energy source fully cfiarged; 
external energy supply disconnected 

Open equipment General conditions 
55 "C (6.3.3) 
Enclosed equipment 
40 °C 

300 1 000 

According to PFVP (6.3.2.2) 

Tfie PC-system sliall be fully operational. 

Ho loss of retentive data is allowed. 



6.3.7.5.2 Verification of manufacturer's method of changing the energy source 



Table 53 - Change of energy source test 



Reference test 


None 


Requirements references 


Subclause 3.2.2, item 9 of 3.2.3 


Preconditioning 
Replacement of energy source 

Verification after tfie tests 


According to PFVP (6.3.2.2) 

According to manufacturer's specifications 
(energy source may require time to be fully charged) 

According to PFVP (6.3.2.2) 
The PC-system shall be fully operational. 
No loss of retentive information is allowed. 



97 



IS/IEC 1131-2(1992) 

6.3.7.5.3 Verification of ottier requirements 

1) Check the required warning of low energy source voltage (see 3.2.2). {Remove the 
energy source and apply the proper controlled voltage in place of the errergy source.) 

2) If non-rechargeable energy sources are used, verify that design requirements of 
4.11 are met. 

6.3.8 Verification of input/output characteristics 

6.3.8.1 General 

1) Test procedures are not defined in detail hereinafter. Detailed procedures shall be 
agreed upoti by the user and the manufacturer and shall be such that the conditions 
defined in 6.2 shall not be impaired. 

2) Though test procedures are not defined in detail, all tests which are referenced 
shall be performed. 

3) Unless otherwise specified in this subclause, all tests shall be carried out twice on 
the same I/O channel(s): 

First test: at minimum service temperature (T min.), i.e. 5 ""C or 7 min. given in 
2.1.1.1. 

Second test: at maximum service temperature (7 max.), i.e. 40 °C/55 "C or 7 max. 
given in 2.1.1.1 . 

4) It is not required to test more than one analog input channel and one digital input 
channel of each type, but all different types which are represented in the basic 
PC-system shall be tested. 

5) All channels of multi-channel output modules shall be tested (see item 10 of 
3.3.2.3). 

6.3.8.2 Verification of digital inputs 

6.3.8.2.1 Operating range test 

Requirement reference: subclause 3.3.1.2 
(Verify that all requirements are met) 

Test procedures; Under consideration. 

6.3.8.2.2 Reversal of signal polarity test (withstand test) 

Requirement reference: Item 4 of 3.3.1.4 

Test procedure: 

A signal of reverse polarity for digital inputs shall be applied for 1 s. 

Verification: 

The results shall be as stated by the manufacturer. The device shall pass the PFVP (see 

6.3. 2. 2). Protective devices such as fuses may be reset prior to verification. 



98 



IS/lEC ,1131-2 (1992) 

6.3.8.2.3 Verification of other requirements 

Verify that the general requirements for digital l/Os under 3.3 and the requirement of 
3.3.1.3 are met. 

6.3.8.3 Verification of digital outputs 
6.3.8.3.1 Operating range test 

Requirement reference: subclauses 3.3.2.1, 3.3.2.2 and 3.3.3.1 
(Verify that alt requirements are met) 

Test procedures: 

- Current range: Under consideration. 

- Voltage drop: Under consideration. 

- Leakage current: Devices/circuits intended for output protection shall not be 
removed. 

- Temporary overload: According to lEC 947-5-1, {AC-15 or DC-13, as applicable). 
For short-circuit proof outputs, the current values shall be respectively 20/^/2 /^ ("two 
times the rated value", as given in 3.3.2.2). 



99 



IS/I EC 1131-2(1992) 



6.3.8.3.2 Test of protected, not-protected, and short-circuit proof outputs 



Table 54 - Overload and short-circuit tests for digital outputs 



Reference test 


None 


Requirements references 


Subclau 


ses 3.3.2.2 (a.c. outputs) and 3.3.3.2 (d.c.outputs) 


Preconditioning 




According to manufacturer's specifications 




Details of mounting/support 




According to manufacturer's specifications 




Loading 


It is sufficient to check one I/O channel of each type under test 


Initial measurements 




According to PFVP (6.3.2.2) 




Description of the tests 

• prospective currents (/f x / ) 


A 


B 


C 


D 


E 


1.2/1,3 


1,5 


2 


5 


21 




(note 1) 










• duration of test (min) 


5 


5 


5 


5 


5 


• order of trials 












first series (at 7 min.) 


1 


2 


3 


4 


5 


second series (at 7 max.) 


6 


7 


8 


9 


10 


• time intervals between tests 




10 min ^ time intervals s 60 min 




Application of tfie tests 




1 




• protected outputs 


Yes 


Yes 


Yes 


Yes 


Yes 


• stiort-circuit proof outputs 


No 


No 


Yes 
(note 2) 


No 


Yes 
(note 4) 


• not-protected outputs (note 3) 


No 


No 


Yes 
(note 2) 


No 


Yes 
(note 4) 


Measurement and verification 




See requirements in 3.3.2.2 and 3.3.3.2 




• durinrg tfie overload 


1 


•Jo evidence of risk of fire or electrical shoe 


< 


• immediately after overload 


M 


aximum temperature rise of the I/O insulati( 
shall not exceed the value of 4.4.2 


3n 


• after overload and proper resetting 




According to PFVP (6.3.2.2) 




NOTES 








1 1,2 for a.c. outputs, 1,3 for d.c. 


outputs. 






2 For currents in the range of two 


times to 20 ti 


mes / , the module may require repair or i 


e place - 


men!. 








3 Protective device(s) to be provid 


ed or specifier 


) by the manufacturer shall be installed. 




4 Protective device(s) shall opera 


te. They shall 


be reset or replaced as applicable for the f( 


jllowing 


test. 








5 An alternative method for testing 


1 of protected ( 


jutputs ts under consideration. See annex E 





100 



IS/IEC 1131-2(1992) 



6.3.8.3.3 Reversal of signal polarity test (withstand test) 

Requirement reference: item 13 of 3.3.2.3 

if the equipment is designed to prevent reversal of signal polarity, the withstand test may 

be not carried out and replaced by proper visual inspection. 

Test procedure: 

A signal of reverse polarity for digital d.c. outputs shall be applied for 10 s. 



Verification: 

The results shall be as stated by the manufacturer. 

The device shall pass the PFVP (see 6.3.2.2.). Protection devices such as fuses may be 
reset prior to verification. 



6.3.8.3.4 Verification of other requirements 

Verify that general requirements for digital l/Os under 3.3 and the remaining requirements 
of 3.3.2.2 are met (output indicators and eiectromechanical relay outputs). 



6.3.8.4 Verification of analog l/Os 

6.3.8.4.1 Operating range tests 

Requirement reference: subclause 3.4.1.1 
(Verify that all requirements are met) 

Test procedures: Under consideration. 

6.3 .8 .4.2 Overload withstand test for analog inputs 
Requirement reference: Item 7 of 3.4.1.2.1 

Test procedure: Under consideration. 

Measurement and verification 

- During loading: 

During the application of specified maximal overload, no physical damage or abnormal 
phenomenon (smoking, smelling, overheating) shall be detected. 

- Alter the test: 

The accuracy shall be verified for the minimal and the maximal value of the input range 
according to PFVP (see 6.3.2.2). 

6.3.8.4.3 Short-circuit test (voltage output) and open circuit test (current output) 

When the short circuit (for a voltage output) or the open circuit (for a current output) is 
realized, no physical damage or abnormal phenomenon (smoking, smelling, overheating) 
shall be detected. After the test, perform the proper functional verification procedure of 
6.3.2.2. .,0, 



IS/IEC 1131-2(1992) 

6.3.8.4.4 Votiage supply variation test 

This test shall be performed when the analog I/O modules are externally energized by an 
independent power supply (i.e. independent from the other I/O modules power supply(ies) 
of the basic PC-system). 

The power supply is replaced by a variable power source. The voltage is adjusted to the 
extreme values pf the specified range of voltage supply. The module shall then pass the 
PFVP and the output variations shall be inside the specified range (see 6.3.2.2). 

6.3.8.4.5 Reversal of signal polarity test (withstand test) 

Requirement reference; item 11 of 3.4,1.2.3 

If the equipment Is designed to prevent confusion of signal polarity, the withstand test may 

not be carried out and replaced by proper visual inspection. 

Test procedure: 

A signal of reverse polarity for unipolar analog inputs shall be applied for 10 s. 



Verification: 

The results shall be as stated by the manufacturer. The device shall pass the PFVP (see 

6.3.2.2.). Protection devices such as fuses may be reset prior to verification. 



6.3.8.4.6 Verification of other requirements 

Type tests are not required; all characteristics non-tested shall be verifiable, under a proce- 
dure to be agreed upon by the manufacturer and the user. 



6.3.9 Verification of MPU characteristics 

Requirement reference: sut)clause 3.6 

Type tests are not required; all characteristics non-tested shall be verifiable under a proce- 
dure to be agreed upon by the manufacturer and the user. 



6.3.10 Verification of remote I/O stations 

6.3.10.1 Response time test 

Requirement references: item 4 of 3.7,2 and item 5^ of 3.7.2 

This test verifies the effect on transfer time(s) introduced to provide remote input inform- 
ation and RIOSs status to the application program and to transmit its logical decisions to 
remote outputs. 

Procedure: 

An application test program consisting of copying input status to outputs is run in four 

similar configurations: 



102 



IS/IEC 1131-2(1992) 

- local inputs to local outputs 

- remote inputs to local outputs 

- local inputs to remote outputs 

- remote inputs to remote outputs 

Pass/fail criteria: 

The total system response times and the subsequent variations of transfer trme(s) shall 

conform to the manufacturer's published specifications. 

6.3.10.2 Loss of communication test 

Requirement references: item 2 of 3.7.1, item 3 of 3.7.1 and item 6 of 3.7.2 
When communication is removed, outputs shall assume a manufacturer's specified state 
within a manufacturer's specified Interval without erratic or unintended behaviour, and the 
communication error shall be signaled to the user. 



Procedure: 

The test is performed by disconnecting a) the link, b) the RIOS external power supply, and 
observing the behaviour of the basic PC-system (i.e. of the MPU as well as of the ^lOS 
and of their outputs). 

Pass/fail criteria: 
According to requirements. 

6.3.1 0.3 Verification of other requirements 

Type tests are not required; alt characteristics non-tested shall be verifiable under a proce- 
dure to be agreed upon by the manufacturer and the user. 



6.3.11 Verification of peripheral characteristics 

Requirement reference: subclause 3.8.1 

Type tests are not required; all characteristics non-tested shall be verifiable under a proce- 
dure to be agreed upon by the manufacturer and the user. 



6.3.1 2 Verification of basic PC-system self-tests and diagnostics 

Requirement reference: subclause 3.11.2 

Type tests are not required; all characteristics non-tested shall be verifiable under a proce- 
dure to be agreed upon by the manufacturer and the user. 



6.3.1 3 Verification of markings and manufacturer's documentation 

Requirement references: subclause 4.12 and clause 5 
Verify that requirements of 4.12 and clause 5 are met. 



103 



IS/IEC 1131-2(1992) 

6.4 Routine tests 

6.4.1 Dielectric strength tests 

The manufacturer sha^l either perform the standard test (see 6.4.1.1), or the optional test 
(see 6.4.1.2) 

6.4.1 .1 Standard dielectric strength test (withstand test) 

Table 55 - Standard routine a.c. and d.c. dielectric strength "withstand test 



Requirement reference 


Subclause 3.10 


Selection of sample(s) 

• SELV circuits 

• < U i 50 

. 50 <U^ 

Test methods and application points 


No test 

Sample testing according to manufacturer's 
instructions 

All units shall be tested 

As specified in 6.3.6.1.1 (note 1) 


Rated voltage of circuit Ue 
(V a.c. r.m.s. or V d.c.) (note 3) 


Test voltages at m altitude (note 2) 
<V) 


For basic and 

supplementary 

insulations 


For reinforced 

insulation 

(note 4) 


Impulse, 

peak 1 ,2/50 )is 

(note 5) 


A.C. r.m.s. 


D.C. 
(note 6) 


< L/g < 50 

50 < U^ < 10O 

100 < U^ < 160 

150 < U^ <300 
e 

300 < U^ <600 

6 


< t/g < 50 

50 < Ug < 100 

100 < t;^ < 150 
e 

150 <'Ug < 300 

300 < U S 600 
e 


500 
800 

1 500 

2 500 
4 000 
6 000 


350 

560 

1 060 

1 780 

2 830 
4 230 


500 
800 

1 500 

2 500 
4 000 
6 000 


Pass/fail criteria 


There shall be no unintentional flashover or breakdown of the insulation 

during the. test. Eventual operation of the protecting devices 

provided on the units shall not be considered as a failure. 


NOTES 

1 When the assembly includes an equipotential conductor isolated from the accessible exposed 
conductive parts, it shall be regarded as an isolated circuit and shall be tested to the same voltage 
as the assembly to which it belongs. 

2 See annex D: correction factor for testing at other altitudes. These test values are 1,27 times 
smaller than applicable type test values. 

3 Rated voltage at the field wiring terminals of the device or circuit. 

4 Class II and applicable class III circuits. 

5 1 ,2 fxs rise time; 50 ^is wide at 1/2 amplitude; 0,6 J maximum energy. 

6 Pulsed d.c; pulsed width: 10 ms, rise and fall times not less than 1,2 ^s. 



104 



IS/IEC 1131-2(1992) 



6.4.1 .2 Alternative dielectric strength test (withstand test) 
(for class I equipment only) 



The manufacturer may elect to use the following test which is more stringent than the 
standard test required in 6.4.1.1 for all rated voltages U^ smaller than 150 V. However, it 
must be noticed that the minimum values of clearance and creepage distances which are 
required in 4.3 may not be large enough to pass this test: therefore, in that case, it is 
recommended to refer to lEC 664 for designing the PC-system, and to adapt subsequently 
the values of the dielectric type test (see 6,3.6.1.1), where applicable. 



Table 56 - Alternative routine a.c. and d.c. dielectric strength withstand test 



Selection of sample(s) 

• SELV circuits 

• < t/^ £ 50 

e 

• 50 < Ug 

Test methods and 
application points 

Dielectric test 
duration 


No test 

Sample testing according to manufacturer's instructions 
All units shall be tested 

As specified in 6.3.6.1.1 (note 1) 

It is the option of the manufacturer to perform the 1 s or 1 min test 




Test voltages and durations (note 2) 


Rated voltage U 
(V) ^ 

(note 3) 


A.C. voltage r.m.s. 
(V) 


D.C. voltage 
(V) 


1 min 


1 s 


1 min 


1 s 


50 <U^ < 600 


500 
1 000 + 2 U^ 

6 


600 

1.2 X 
(1 000 +2 U^) 


700 

1.414 X 
(1 000 + 2 U^) 


850 

1.414x1,2x 
(1 000 + 2 U^) 


Pass/fail criteria 


There shall be no unintentional flashover or breakdown of 

the insulation during the test. Eventual operation of the 

protecting devices provided on the units shall not be 

considered as a failure. 


NOTES 

1 When the assembly includes an equipotential conductor isolated from the accessible exposed 
conductive parts, it shall be regarded as an isolated circuit and shall be tested to the same voltage 
as the assembly to which it belongs. 

2 Regardless of altitude. 

3 Rated voltage at the field wiring terminals of the device or circuit. 



105 



!S/!EC 1131-2^1992^ 



6.4.2 Protective earthing continuity test (withstand test) 

This test is intended to verify acceptable earthing continuity for all accessible metal parts 
intended to be earthed. The test shall be performed on all non-SELV rated voltage units. 



The application points are between the earthing terminal or contact and the accessible 
metal parts intended to be earthed. 

The resistance shall not exceed 0,1 O. 



.106 



IS/1 EC 1131-2(1992) 

Annex A 

(normative) 

Illustration of PC-system hardware definitions 

The following figure A.I illustrates the hardware in the PC-system as defined for the 
purposes of parts 1 and 2 of lEC 1131. 



MAIN REMOTE PERMANENT 

PROCESSING INPUT/OUTPUT PERIPHERALS 

UNIT STATIONS 



MPU 



RIOSs 



NON PERMANENT PERIPHERALS 

NOT PLUGGABLE PLUGGABLE 
ON-LINE ON-LINE 



NON TRANSPORTABLE 



TRANSPORTABLE 



PORTABLE 
HAND-HELD- PORTABLE 



PROGRAMMABLE CONTROLLER 



PERIPHERALS 



PERMANENT INSTALUTION 



NON PERMANENT INSTALLATION 



PROGRAMMABLE CONTROLLER SYSTEM (PC SYSTEM) 



lEC 96il92 



Figure A.I - Programmable control system (PC-system) 

Transportable, portable and hand-held portable peripherals have specific requirements 
and have to be distinguished from permanently installed peripherals (see 2.1.3.3, 3.9.2 
and 4.5.3). 



107 



IS/lEC 1131-2(1992) 



Annex B 

(normative) 

Input table equations 



The following equations were used to generate table 9 In 3.3.1 .2 (with some exceptions 
explained in the notes). 



D.C. equations 

L/Hmax. = 1.25 U^ 

Wmin. = 0.8l/„-t>d,,p-1V 

tyr max. = L/Hmin. 

t/Tmin. = 0.2 U^ 

UL max. = L^H min. (t < /Tmin.) 

UL min. = -3 V (24 V d.c.) 

UL min. = -6 V (48 V d.c.) 



UH max. - UT min. 



/Tmin. = 



A.C. equations 

t;Hmax. = 1.1 U^ 

Wmin. = 0.85ty„-ty^,,p-1 V 

UT max. = L'Hmln. 

tyr min. = 0,2 U^ 

l/L max. = UHmin. (/< /Tmin.) 

UL min. = 



(notes 1 et 2) 
(note 1) 



/Tmin. = 1^^^^ + 1 mA (nominal voltages < 120 V) 
/Tmin. = ^^^^^^ + 2 mA (nominal voltages > 120 V) 



2 = Empirical worst case relay contact 
Open contact impedance = 100 ka 
UL min., = ND (Not defined) 



IL min. = 



Type 1 inputs: 

IH max. = /Tmax. = IL max. = 15 mA 
IH min. = /Tmin. + 1 mA 
^drop = 3 V (3,3.3.1) 

Type 2 inputs: 

IH max. = IT max. = IL max. = 30 mA 
IH min. = l^^^^^ + 1 mA 
'i««k = /7'max. = 1,5 mA 
U,,^^ UD max. = B\/ 
= I min. =5 mA 



hold 



NOTES 



Type 1 inputs: 

IH max. = IT max. = IL max, = 15 mA 
IH min. = /Tmin. + 1 mA 
^drop = 5V (3.3.2.1) 

Type 2 inputs: 



Note 3 



IH max. = /Tmax. = /L max. = 30 mA 
IH min. = l^,^^^ + 1 mA 

'leak = 'n "^^x- = 3 "^A 

^ ax. »10 

= 5 mA 



^drop = ^^ ^^^- == 10 V a.c 
= I min 

a 



hold 



(note 4) 
(note 4) 
(note 4) 



1 For all 100/110/120 V a.c. and all 200/220/230/240 V a.c Inputs. U has been respectively selected as 
100 V a.c. and 200 V a.c, in order to allow compatibility of a single moaule with various supply voltages. 

2 1 V drop (a.c. r.m.s. or d.c.) is assumed for the connecting leads. 

3 Maximum values of voltage drops of digital outputs for d.c. and a.c. 

4 These values of l^^^^^, U^^ and l^^^f^ are also those adopted in lEC 947-6-2. 



108 



ISAEC 1131-2(1992) 



Annex C 

(informative) 

Reconunended higher immunity levels for electrical noise tests 



If higher immunity levels than the minimum stated in 3.9.1 are required, the following 
electrical noise severity levels given in table C.I below are recommended as standard. 



When severe tioise conditions exist, levels higher than those given in this table are subject 
to agreement between the manufacturer and the user. 



For further information regarding description of typical noise producing environments and 
the approximate severity levels, see lEC 1131-4 and lEC 801. 



Table C.1 - Electrical noise tests for PC-system and stand-alone peripherals 
(notes 1 and 2) 

Recommended levels higher than minimum required 



Electrical noise tests 


Electrical noise severity levels 


Notes 




Maximum surge 

energy 

Minimum source 

impedance 


All power 
supplies 


Digital l/Os 


Digital l/Os 
t/g < 24 V 

Analog l/Os. 
communication l/Os 


Electrostatic discharge 
- Level RH-2: ESD-4 


150 pF/150 n 


15 kV 


15 kV 


15 kV 


3 and 4 


Radiated electromagnetic field 


- 


10 V/m 


lOV/m 


10 V/m 


3 


Conducted noise 
- Fast transient 
Common mode 


4 mJ/spike at 2 kV 
on 50 n 


4kV 


2kV 


0,5 kV 


3 


- Damped oscillatory wave 
Series mode 


200 11 


2kV 


2kV 


- 


3 and 5 


For notes 1 , 2. 3, 4 and 5, see tc 


ible 16 in 3.9.1. 





109 



IS/IEC 1131-2(1992) 



Annex D 

(normative) 

Correction factors for test voltages 



Table D.I - Correction factors for test voltages corresponding to barometric 
pressure or altitude 



Altitude of test 


Barometric pressure 


Correction (multiplication) 
factor for test voltage 


m 


kPa 


(note) 





101,3 


1,27 


500 


95,0 


1.19 


1000 


90,0 


1.13 


2 000 


80,0 


1.00 


3000 


70,0 


0.88 


4000 


62,0 


0,78 


5 000 


54,0 


0,68 


6 000 


47,0 


0,59 


7000 


41,0 


0.51 


8000 


35,5 


0,44 


NOTE - At a given altitude 


, corrections for normal variations i 


n barometric pressure are 


disregarded. 







110 



IS/IEC 1131-2(1992) 



Annex E 

(informative) 

Testing of prot&cted outputs 



The ioliowing alternative method is under consideration for testing of protected outputs in 
addition to the method given in 6.3.8.3.2. 

in the case of protected outputs, tests A, 6, C, D and E may be replaced by the following 
method: 

Test procedure: 

- First series (at 7 min.) 

• Search and measurement of the threshold / of the protective function while 
causing the output load to vary slowly by using a variable resistor: 

• then, submitting the protective function to two tests of 5 min each, during which 
the protected output is loaded respectively at 1,1 / (prospective current) and at 
0.9 /p. 

- Second series {at 7 max.) 

• Same as first series, but at 7 max. 

Measurement and verification: 

- As specified in 6.3.8.3.2. 



111 



hKCMtiLD Af SlAiCO fRiNltNG ^ItlSS, D>E«.UMiq](IA